[cpp] Add _Complex as a special keyword (thanks gcc).  Allow keyword remapping in package names.  cpp.FastIterator is extern but not generic, but do not 'fix' its overrides.  Do not generate code for the base KGeneric def

git-svn-id: http://haxe.googlecode.com/svn/trunk@6484 f16182fa-f095-11de-8f43-4547254af6c6