Added a new class with useful sql queries: merge after restriction_to_collection

Autor	SHA1 Mensaje	Fecha
tanja	8a4a4e3aff fixed a type in get_field_mapping in ParseMapping	hace 4 años
tanja	97e3e26d61 minor fix in schema dereferencing: solved the problem with ' in schemas	hace 4 años
tanja	2c07703595 added possibility to change source and target names in the get_field_mapping method in ParseMapping	hace 4 años
tanja	7f8ae4956f added SQLQueries class	hace 4 años
tanja	316f568a5c resolved conflicts: added deferenced schema	hace 4 años
tanja	a975d9151b change in ParseJsonSchema	hace 4 años
tanja	62e0527dec fixed a typo	hace 4 años
tanja	2d8a0954db added restriction to a mongo collection to a constructor	hace 4 años

#2 Added a new class with useful sql queries: merge after restriction_to_collection