Fixed the hlint stuff (except for one redundant do, see --exportAST TODO below).

-i, -o, -h seem to work as intended.

Tested:
compile to stdout:
-i HelloWorld.rail -c
compile to hello.llvm
-i HelloWorld.rail -o hello.llvm -c

Not Working yet:
--exportAST is not working and therefore ignored at the moment (TODO: uncomment Main.hs line 86 and fix it)

Untested (due to not working --exportAST):
--importAST