Janus evaluation

[casvdrest]

Some notes about the integration of eval and QQ:

• There are still A LOT of issues with naming
• I disabled all semantic checks since they require the Hanus program to have a 'main' function and the above messes everything up
• Apparently the XOR operator triggers an infinite loop when spliced

[joristt]

Couple of things we still need to fix:

• [x] eval uncall / implement reverse proc generation.
• [x] don't ignore type signatures of declared global / local variables
• [x] return local variables
• [x] check that only locals can be passed to a function The above already works, to the extent that you get a "Conflicting definitions for " error, which I can live with personally.
• [x] make local vars reference types instead of value types.
• [x] assert that local var is indeed the value stated at the unlocal block.
• [ ] fix that you can't declare multiple while-loops.
• [ ] loop inside loop?
• [x] arrays / field indexers.