Add magic comment to encoding_spec
Add more specs based on wqparser test cases
Passes specs for zero-length method name (as :call)
Passes spec for valias with backref
Fix bad autogenerated specs for rational literals
Passes specs for op_assign when lhs is not an lvar and op is not && or ||
Add partial handling for preexe (needs special attention with rbx-integration later)
Update README with some basic useful information