SCUMM: Fix bug 6739 - Untranslated dialogs
PRINCE: Allow to load translation file - prince_translation.dat

Update detection file to allow English language with both PL and DE data files. Add setMobTranslationTexts() to update mob names to translated ones in each location
PRINCE: Change PrinceGameType enum names

Fix compilation on gcc
SCI: properly reversed color matching thanks wjp
SCI: color matching - remove debug code
SCI: color matching bug fix
SCUMM: Disallow saving while a room 'prequel' is shown in v0-v3 games

These are cases where the screen is completely blank, showing text.
In such cases, no room is set, thus no room resources are available.
An example is the screen shown after the credits in the Zak FM-TOWNS
intro ("The next day..."). Thanks to segrax for finding this case.
This commit is based off pull request 522, but completely disallows
saving in such scenes, instead of adding explicit checks for them
Merge pull request #523 from BenCastricum/fixforbug6739

SCUMM: Fix bug 6739 - Untranslated dialogs
HOPKINS: Add specific code to handle the butchered Polish version with sync sound
HOPKINS: Fix a couple of comments
AUDIO: Add override specifiers
BACKENDS: Add override specifiers
BASE: Add override specifiers
COMMON: Add override specifiers
ENGINES: Add override specifiers
GRAPHICS: Add override specifiers
GUI: Add override specifiers
IMAGE: Add override specifiers
VIDEO: Add override specifiers
AGI: Add override specifiers