[svn r112] Fixed 'case 1,2,3:' style case statements. Fixed a bunch of bugs with return/break/continue in loops. Fixed support for the DMDFE hidden implicit return value variable. This can be needed for some foreach statements where the loop body is converted to a nested delegate, but also possibly returns from the function. Added std.math to phobos. Added AA runtime support code, done ground work for implementing AAs. Several other bugfixes.