Added --force back to sql:insert command.

Made also --sql-dir configurable and changed its default value to %app_dir%/propel/sql like in propelBundle v1.
Added --overwrite optin to sql:build command to allow overwriting the sql.map file without the need to remove it manually.

Made also --sql-dir configurable and changed its default value to %app_dir%/propel/sql like in propelBundle v1.
Fixed AbstractCommand to work with newest Propel2 version. Added option `index_property` back to ModelType.

Basically copied newest changes from propelv1 symfony bridge to ModelChoiceList to have more fixes included.
Fixed also some typehints.