Update of the build system

- The results of C++ feature detection are now cached.
- The results of GL extension detection are now cached.
- Reorganized the cmake scripts.
- Added generation of a python script that contains info about
  the configuration of the current machine.
- The configure.py's --gl-header-lib option was renamed to --gl-api-lib.
- Added a utility script for testing if all available configurations
  build properly.
Merge branch 'release-0.33.0' into develop

Conflicts:
	CMakeLists.txt
Added readme file for assets download page
Updated the configure.sh script

- Updated the script to match the new cmake options.
- Replaced the --build-and-install option with separate --build
  and --install options.
Fixup in the configure.sh script
Update in the build system scripts

- Added the --generator option that allows to specify the cmake generator
  to be used.
- Added bash-completion for the --generator option that allows to complete
  the name of the generator on-the-fly from supported generators.
Update of the build system and scripts

- Simplified the configure.py script.
- Added the --for-msvc option to the configure.bat script.
- Fixed a bug in the main cmake script.
Multiple changes

- Updated the circular_logo images.
- Updated the make_video scripts to overlay the logo on videos.
Multiple changes

- Updated GL version detection.
- Minor addition to a standalone GL example.
Minor update in GL version detection
Turned some functions into library functions
Turned some functions into library functions
Minor update in gl.hp

- Added the definition of GL_VERTEX_ARRAY if it is missing.
Fixup of the previous commit
Updated program interface functions and enums

- Added the ProgramResourceProperty enumeration.
- Added new functions to ProgramInterface.
Fix in ProgramResource

- Fixed problems with linking the library in GL 4.3 is not available.
Backporting to MSVC 10
Backporting to MSVC 10
Backporting to MSVC 10
Backporting to MSVC 10