Initial implementation of new MCString methods.
Implemented MCStringCreateWithCharsAndRelease
[[ RefactorSyntax ]] Corrected tooltip property type.
[[ RefactorSyntax ]] Fixed UTF8 encode / decode.
[[ UnicodifyGraphic ]] Changed assign to retain in copy constructor.
[[ UnicodifyTooltip ]] Ensured array index lookups start at 1.
Make sure use of unicode when using IO_read/write_stringref is explicit.
Added check for nil string when using IO_read_stringref_utf8.
Merge branch 'refactor-syntax_unicode' into refactor-syntax_unicode_mac

Conflicts:
	engine/src/dskmain.cpp
Make sure we clear globals on desktop.