Improvements to location information

[jeromesimeon]

Support for parsing location through the compiler is mostly in place. Some additional improvements:

• ~better location improvements for CTO files (accessed from CTO parser), e.g., for import~
• [x] add file information to location when available
• ~possibly add location information downstream to Q*cert AST -- may be necessary for JavaScript map~
• [ ] Remove as many (all?) of the use of dummy_provenance

[kach]

• [ ] location info for failed enforce, inserted automatically during the ergocalculus compilation step

[jeromesimeon]

Note: having access to file (or "module") information in the provenance is important when dealing with multiple modules so should be considered a feature for contract modularity.