Added the first files to a devel/testing EGL imp.
Started release-0.40.0
Minor update in build testing script
Fixes problems in the build system

- Fixed a problem with building of the oglplus library.
Updated GL version detection

- Updated the build system to generate the oglplus/fix_gl_version.hpp header.
- Updated the examples to use this header.
Renamed the QTGL init-lib id to QT4GL
Added Display-related function to the EGL impl.

- Updated the internal devel/testing implementation of EGL
  - Added initialization/cleanup functions
  - Added display-related functions.
Multiple fixes

- Fixed a problem in pango/cairo detection.
- Reorganized the library include  headers.
- Minor file documentation fix.
Fixed an invalid ifdef GL extension test.
Added fix_gl_version.hpp for the MSVC solutions

- Added an empty fix_gl_version.hpp files for the manually created
  MSVC10 and MSVC11 solutions.
MSVC Warning fix in Buffer::ImutableStorage
Fixed a typo/bug in the build system
Update of changelog
Merge branch 'release-0.40.0' into develop