GL: Request OpenGL 2.1 compatibility profile

This might help with some newer OpenGL drivers (hopefully).
Merge branch 'master' into ui-alerts
Refactor|Log|libdeng2: Renamed the INFO/Important level to Note

“Note” as in “please note this important detail”. Also, the term
“info” is already used for Info files.
Spelling
libdeng2: Updated logging with domain-specific LOG macros

Also, tweaked the entry levels to be more suitable within the domain.
libgui: Updated logging with domain-specific LOG macros

Also, tweaked the entry levels to be more suitable within the domain.
Shell|libshell: Updated logging with domain-specific LOG macros

Also, tweaked the entry levels to be more suitable within the domain.
DehRead|WadMapConverter: Updated logging with domain-specific LOG macros

Also, tweaked the entry levels to be more suitable within the domain.
Client: Started updated logging with domain-specific LOG macros

Also, reworded some messages to be more appropriate for the context
and usage.