Updates (removal of MCStringGetCString calls) on common mobile-related files
updates after feedback 1/2
updates after feedback 2/2
Removed some MCValueRelease() calls that were not correct
Updates on MCUrlProgressEvent class plus some more updates from char* to MCStringRef
updates after feedback part 1/2
Updates after feedback part 2/2
Merge remote-tracking branch 'upstream/refactor-syntax_unicode' into refactor-syntax_unicode_MblCommon

Conflicts:
	engine/src/mblspec.cpp
Reverted changes to as MCSLoadUrlState->url to be a MCStringRef (not a MCDataRef)
Updates after Seb's feedback (changed send_url_progress() signature plus some more updates)
Removed iphone_test.rev file so as to compile
Merge remote-tracking branch 'upstream/refactor-syntax_unicode' into refactor-syntax_unicode_MblCommon

Conflicts:
	engine/engine-mobile.xcodeproj/project.pbxproj
	engine/src/mblspec.cpp
Merge branch 'refactor-syntax_unicode_MblCommon' into refactor-syntax_unicode