Merge branch 'release-0.36.0' into develop
Minor documentation update
Replaced reserved identifiers

- Replaced identifiers that are technically reserved for the implementation
  by the standard.
Added the SimpleSubdivSphere shape builder
Minor update of oglplus example
Multiple changes

- Added an example showing the SubdivSphere shape builder.
- Renamed one of the older examples.
Replaced identifiers reserved by the C++ standard

- Replaced all remaining occurences of idenifiers with the \<_[A-Z]
  pattern defined in oglplus sources.
Documentation update

- Added a simple tutorial explaining how to build oglplus into a library.
Moved the documentation headers to the doc folder
Multiple changes

- Updated the detection if the library can be built in the build system.
- Moved the includes related to PNG loading between files.
- Added missing include file to oglplus example.
Minor update of readme
Fixed a problem in Texture::SwizzleRGBA

- The getter function now returns a value of TextureSwizzleTuple.
- The setter was split into three different functions.
- All SwizzleRGBA functions now properly work with the full tuple instead of
  getting/setting a single value.
Update of TextureSwizzleTuple

- Added the Red, Green, Blue and Alpha functions as alternate for the SwizzleX
  functions.
Minor updates to TextureSwizzleTuple

- All member functions previously returning void now return *this.
Minor updates of the build system
Fixed typo in model name
Updated the oglplus::BufferTarget enumeration.
Added support for ARB_seamless_cubemap_per_texture
Updates in oglplus::Sampler

- Added sampler parameter getter functions.
- Updated the error reporting to be more precise.
Updated the PixelDataFormat enumerations

- Added the velues from the ARB_texture_stencil8 extension.