Documentation and minor fix in OALplus

- Fixed a bug in listener gain getter.
Update of the configure.py script

- Added support for automatic generation of man-compatible manual.
Update of the configure.py script
Re-generated the config script manual
Minor documentation update
Updates in the build system

- Reimplemented the GL context initialization library selection.
- Renamed the --use-gl-window-lib options of the configure script
  to --use-gl-init-lib
- Re-generated the config script manual and bash-completion.
Update in one of the OGLplus examples
Added EGL example harness for off-screen rendering
Minor fix in an EGLplus example
Minor documentation update in oglplus Plane
Update of the Python bindings

- Added bindings for oglplus Plane and Vector.
- Updated bindings for Angle.
- Added a new example.
Updated the Vector Swizzle implementation

- The Swizzle classes are generated by a script now.
Merge branch 'develop' into feature-boost-python
Updated the Python bindings for OGLplus

- Added bindings for Swizzle*(Vector).
Merge branch 'feature-boost-python' of github.com:matus-chochlik/oglplus into feature-boost-python