- Change distinct -> typedef.

- Order of attribute declaration is changed for `alias`.
- Added `LANGUAGE_DEV_VERSION` env constant.
- Rename `anyfault` -> `fault`.
- Changed `fault` -> `faultdef`.
- Added `attrdef` instead of `alias` for attribute aliases.

test/test_suite/statements/if_only_throw.c3t

@@ -2,7 +2,7 @@
 module foo;
 import std::io;
 
-fault ABC;
+faultdef ABC;
 
 fn void? test()
 {