`for` loop support about ccoscope HOT 1 CLOSED

I tinkered a bit with it and decided to reuse WhileExprAST::codegen as a helper.
The implementation is buggy now though, so I created a new branch (5e42b84).
When trying to compile examples/forloop1.cco we get enigmatic:

Parsing ../examples/forloop1.cco
Found 0 prototypes and 1 function definitions.
CCoscope: /home/ja/llvm/src/lib/IR/Constants.cpp:2040: static llvm::Constant* llvm::ConstantExpr::getGetElementPtr(llvm::Type_, llvm::Constant_, llvm::ArrayRefllvm::Value*, bool, llvm::Type*): Assertion `Ty == cast(C->getType()->getScalarType())->getContainedType(0u)' failed.

I don't know whether it's a clang 3.x vs 3.y issue or I screwed up something :P

UPDATE
As problems seem not to be related to for loop implementation, I merge forLoop branch with master.

from ccoscope.