Implemented row filtering and skipping;
Implemented rows filter for budgets/actuals to skip rows with no value in amount column
Fixed lookup generation with full and unique keys for all objects;
Fixed scopes and paths resolving for parents and inverses;
Fixed DataCollisionError init and added to it columns and values;
Implemented inverses related errors
Merge branch 'develop' of https://github.com/prjts/open-budget into develop
Fixed _generate_scops to take into account parent template;
Added parent scope error throwing in _generate_scops  for unresloved rows;
Implemented _skipped_row
Implemetned _generate_lookup for re-using the template_parser's generated lookup and rows lookup