Adds const operator[] to TByteObject

Issue: #32
Adds base types for Smalltlak instruction API

Commit provides basic data structures for
operating Smalltalk bytecodes in a friendly way.

Base concept is stolen drom the LLVM and other
software which deals with basic blocks and so on.

Issue: #32
Adds TParsedMethod::parse()

Parse method provides a way for translating
compiled Smalltalk method into intermediate
form convinient for analysis and modification.

After method is parsed, one may traverse it
using basic block or instruction iterators.

Issue: #32