Updates in object wrapper

- Added constructors allowing explicit specification of GL object creation
  method (glGen* vs. glCreate*) to Object.
- Documentation updates.
Merge branch 'release-0.50.0' into develop
Updated the news feed source + the workflow script
Documentation update
Moved the DSA object wrappers to ./dsa/ext/
Multiple changes

- Added detection of GL_ARB_direct_state_access to the build system.
- Added if GL_ARB_direct_state_access #ifdefs.
- Minor documentation updates.
Added wrapper for ARB_texture_barries
Multiple DSA-object-related changes

- Renamed the EXT_d_s_a-based wrapper class to DSA*EXT.
- Added new GL_4_5/ARB_d_s_a-based wrappers (W.I.P.).
Minor changes in the new DSA wrappers (WIP)
Added wrapper for BlitNamedFramebuffer
Updated the QueryTarget enumeration
Multiple changes

- Added the ContextReleaseBehavior enumeration.
- Added the ResetNotificationStrategy enumeration.
- Added the GraphicsResetStatus enumeration.
- Minor updates to the quickbook docs.
Updated the web index page and css
Updated the web index page and news feed source
Updates in the smart-enums for EGLplus / OALplus
Updated the QueryTarget enumeration

- Added values from the ARB_transform_feedback_overflow_query extension.
Updates to the ARB_dsa Texture wrapper
Added wrappers for vertex Array/Attrb DSA ops
Removed the EnumValueType enumeration
Updated the LimitQuery enumeration