Merging GoogleTest

Issue 546

closes #546
closes #37

Fixed and completed tgt::Texture::texelAsFloat() methods to support all data types and number of channels.

refs #37

* Implemented trackball navigation interaction for rendered geometries
* Implemented correct rendering of textures with correct aspect ration (no longer weirdly stretched textures)
* removed obsolete (because redundant) renderFullscreen option

refs #546
refs #37

* DataContainerInspectorCanvas uses the GeometryRenderer processor to render geometry
* DataContainerInspectorCanvas::_textures now uses DataHandle to improve thread safety avoid segfaults
* replaced some function calls with Qt signals to loose coupling
* removed obsolete fields and methods

refs #546

get rid of gcc warning from test-campvis. however, there is one remaining in gtest-internal.h, and a few in concurrenthistogram.h. couldn't figure out the way around for those

Fixed GenericGeometryTransferFunction not setting the clear color correctly before rendering into TF texture.
This also fixes the broken IXPV pipeline (Issue #62) that got also cleaned with this commit.

closes #62

* Reverted some of the changes introduced with 3c7bf8c0: tgt::FramebufferObject now uses EXT functions (instead of core functions) throughout the entire code. Previous mix of EXT and core function calls showed problems with AMD GPUs. All core methods broke results on Intel GPUs.

google test merge request feedback reviewed. addressed all necessary major and minor issues that were pointed out; and hopefully fixed my stupidity in LinearMapping::operator==

rewritten init() with the glcontextmanager instead of qtcontextmanager, updated ImageData, NumericProperty, GenericProperty test codes

added the documentation (brief). added test class for StringUtils. trimmed out the redundant code segments.

added DataContainer, StringProperty aka GenericProperty, NumericProperty test code and reorganized the folders

"MERGED 4 commits - 1. cleaned up googletest 2. solved std_tuple issue with four modified files from current beta googletest 3. MTd-MdT issue resolved with CMake flag 4. googletest produces two projects named gtest and gtest-main. a third project is created linked with gtest-main and all our testing libraries"

* Geometry1DTransferFunctionEditor not correctly drawing image intensity histogram.
* VolumeExplorer not always initializing slice- and raycasting render size properties.

Lightsourcedata

Removed ProcessorDecoratorShading and replaced all of its usages with the new LightSourceData API. This also includes adding LightSourceProviders to the corresponding pipelines.

refs #547

* Introducing base module with LightSourceProvider processor
* Updated GeometryRenderer and GeometryRendererDemo to use LightSourceData instead of ProcessorDecoratorShading
* Introducing LightSourceData::bind()

refs #547

refs #547

Added tgt::FramebufferObject::attachTexture() to check for completeness in debug mode. This should catch and thereby ease debugging of misconfigurations of the FBO that will otherwise lead to errors at some later place.

This reverts commit cedb7a00.

Issue 545

Commit dabdc917 fixed the tgt vector and matrix implementation to follow strict aliasing rules but also changed the semantics of the sub-vector/sub-matrix getters, which previously returned references but after returned copies.
While this did not break CAMPVis code, since nobody relied on it, the original reference semantics were much more intuitive. This commit brings them back but in a valid C++ way not breaking strict aliasing rules.

closes #545

Move invalidation levels from properties to processors

See Issue 542: https://campcloud.informatik.tu-muenchen.de/redmine/issues/542

Fixed CMake build scripts to better handle default enabled modules and specifically disabled modules.

To now, each property hat an _invalidationLevel field that was evaluated by processors when the property had changed in order to determine what has to be done. However, since properties could also be owned by other classes, this design was semantically misleading.
Therefore, it was removed with this commit and replaced by the invalidation map of each processor. Now, this per-processor mapping of property -> invalidation level is managed by the processor itself. Furthermore, the invalidation level is no longer setup during property creation but during AbstractProcessor::addProperty(), which also makes much more sense.

ATTENTION: Due to these intrusive API changes, the code of all processors and other classes handling properties needs to be changed. As a reminder, the implementation of addProperty() also now takes a reference instead of a pointer, so that old code does no longer compile.

refs #542

Merge Ieeevis Predicates

Merging the cleaned code from Christian's IEEE SciVis '14 submission on predicate-based volume rendering.

removed obsolete scr_msk module. Code for Christian's IPCAI '13 submission on orientation-driven ultrasound compounding will be reimplemented from scratch at some point anyway.