Source code refactoring

[arakov]

Proposals for code refactoring:

• simplify - isCompatible - could we get rid of special cases for V_FLAG?
• global attributes : maybe it should contain the string reference, instead of the string itself (data duplication : many class names are already stored) or every record should be aligned to 4/8
• operator names should be configurable
• replace all default maps with optimized ones (e.g. SyntaxHash, TableHash, SyntaxTable)