TSAGE: R2R - Remove some warnings
VIDEO: Fix awful thinko from 55791d5fc1
WINTERMUTE: Remove unused variables.
WINTERMUTE: Make BaseFileManager::registerPackages case agnostic.

The old version did only work as expected when all the filenames were all
lowercase. This seems to be the case for most (or even all?) WME games.
However, we are better safe than sorry and make the code case agnostic.
WINTERMUTE: Remove another unused variable.
WINTERMUTE: Slight interator usage cleanup.
WINTERMUTE: Use const_iterator in BaseFileManager::registerPackages.
COMMON: Add underlying type names to Common::String.

The value_type is analogous to std::basic_string::value_type.
The unsigned_type on the other hand is an unsigned type of the value_type which
allows to obtain an character without nasty sign extension.
COMMON: Add simple UTF-32 string class U32String.
GRAPHICS: Let Font take uint32 as character codes.

This is required to support UTF-32 strings but does not make them work
automatically!
GRAPHICS: Get rid of _glyphSlots in TTFFont.
GRAPHICS: Allow TTFFont to cache glyphs when required.

This should allow TTFFont to display UTF-32 characters from fonts.
GRAPHICS: Allow Font to accept U32String as strings.
WINTERMUTE: Switch WideString to U32String.
COMMON: Document U32String a bit better.
COMMON: Document Common::String::unsigned_type.
TSAGE: Further fixes for object centroid handling
TSAGE: Fix for flub tube maze header comments
GUI: Fix ListWidget::getEditRect's returned height.
GUI: Fix EditTextWidget::getEditRect's returned height.