New execution pipeline

[playXE]

Current execution pipeline looks like this:
AST->Bytecode->Interpreter->FullCodegen JIT

In new pipeline we should try to create size optimized bytecode and new fast interpreter:

1. AST->Bytecode->Interpreter->FullCodegen JIT->MIR->LIR-> Fusion JIT

2. AST->Bytecode->MIR->LIR->CraneliftIR->Binary output

First pipeline is intended for users who want to instantly run program or want to embed Waffle into their programs.
Second one is for mobile devices and when you want to have executable file instead of bytecode file.