rename platform=darwin -> platform={ios,macosx}, fix ios simulator build
update README.md with darwin->{macosx,ios} rename
remove redundant PROTECT usage

This was causing crashes at GC time since we ended up visiting the
same reference twice in a single GC cycle.
Merge pull request #282 from dicej/protect

remove redundant PROTECT usage
Merge pull request #281 from joshuawarner32/darwin-platform-reorg

rename platform=darwin -> platform={ios,macosx}, fix ios simulator build
use arg-parser in type-generator
move Machine::*Type to GcObject::*Type
Generate c++ classes from types.def
generate accessors for array fields
add Code to classpath
include stdc++ <new>
rename assert to assertT, to avoid conflict with std assert macro
generate better typed accessors from type-generator (and switch to using standard library there)
improve type safety in types.def & remove old function-based accessors
Formalize Machine::roots and MyProcessor::roots (for Compiler) in types.def
Generate & use setters from types.def