Update rules and tweak code so that it compiles using 10.6 SDK and i386 arch.
[[ Bugfix 12612 ]] Change block layout to use floating-point

Conflicts:
	engine/src/MCBlock.h
	engine/src/block.cpp
	engine/src/context.h
	engine/src/font.cpp
	engine/src/font.h
	engine/src/graphicscontext.cpp
	engine/src/graphicscontext.h
	engine/src/line.cpp
	engine/src/line.h
	engine/src/metacontext.cpp
	engine/src/metacontext.h
	engine/src/paragraf.cpp
	engine/src/paragraf.h
Merge branch 'refactor-syntax_unicode' of https://github.com/runrev/livecode into refactor-syntax_unicode
Merge branch 'refactor-syntax_unicode' into refactor-syntax_unicode_merge_6.7

Conflicts:
	engine/src/MCBlock.h
	engine/src/line.cpp
	rules/Debug.xcconfig
	rules/Global.xcconfig