Added sonata_type_model_autocomplete form type

Added support for many-to-many in sonata_type_model_autocomplete

Changed `collection` form type to `sonata_type_native_collection`

Fixed unit tests

Fixed issues with Sf 2.3

Fixed dates in changelog

Fixed minor issues

Make code more universal.

Another improvements. Fixed bugs in paging.

Added toStringCallback option. Fixed datagrid parameters.

Fixed unit tests

Improved code coverage of Datagrid

Improved doc and added some more tests

Fixed CS
Merge pull request #1764 from pulzarraider/sonata_type_model_autocomplete

sonata_type_model_autocomplete form type (autocompletion for too many items)
Fixed year in licence headers in some files
Merge pull request #2282 from pulzarraider/year_fix

Fixed year in licence header in some files
Removed support for SensioGeneratorBundle 2.2
test breadcrumbs generation
Merge pull request #2285 from greg0ire/code_coverage

test breadcrumbs generation
Merge pull request #2283 from pulzarraider/remove_abstract_bc_generator

Removed support for SensioGeneratorBundle 2.2
updated ignore files added idea files to ignore list
Merge branch 'sonata-master'