MISC: Fix typo s/Adlib/AdLib/ (only where visible to the user)
GUI: Fix description of game specific extraPath
SWORD1: Change "no DXA support" message.

It's "without zlib" or "without DXA support". WJP prefers the first.
GUI: s/savegame/saved game/

Makes it consistant throughout the GUI
CLI: change "savegames" into "saved games", same as in GUI
CGE2: Silence warning about uninitialized variable.
KYRA: Extend safety check inside AdLibDriver::getProgram.

This also removes an TODO and replaces it with a comment explaining this
safety check.
KYRA: Add safety checks for getProgram/getInstrument return values.

This fixes a crash in Hand of Fate when scaring off the rat by using the
swampsnake potion on Zanthia. This crash is timing sensitive since the game is
stopping the offending sound resource at this point. If it still gets to the
instruction setting up an invalid instrument, it will crash ScummVM with in
invalid read.
KYRA: Constify base type for some pointers in AdLibDriver.
KYRA: Slight cleanup.
GUI: change FullScreen into fullscreen

This makes it consistant with other references to fullscreen.
GRAPHICS: Fix some Doxygen comments that seem wrong.
COMMON: Fix some Doxygen comments that seem wrong.
BACKENDS: Fix some Doxygen comments that seem wrong.
ENGINES: Fix some Doxygen comments that seem wrong.
GUI: Fix some Doxygen comments that seem wrong.
AUDIO: Fix some Doxygen comments that seem wrong.
WINTERMUTE: Remove unused Sqr-function.
Merge pull request #493 from BenCastricum/branch2

MISC: Some minor typo fixes
Merge pull request #495 from somaen/docuFix

Doxygen-fixes