Fixed keeping sort by on listing page paginator

Otherwise, related fields won't work ..
Update travis file
implement dummy version of getUrlsafeIdentifier
Merge pull request #144 from dbu/add-urlsafeidentifier

implement dummy version of getUrlsafeIdentifier
Update Resources/doc/reference/list_field_definition.rst

add "array" reference
Merge pull request #146 from oparadis/patch-2

Update Resources/doc/reference/list_field_definition.rst
Merge pull request #139 from bgaleotti/fix-paginator-order

Fixed keeping sort by on listing page paginator
fix composer for symfony 2.2
Fixed a bug where form didn't switch to multipart/form-data when necessary
Merge pull request #152 from to0om/otm-bugfix

Fixed a bug where form didn't switch to multipart/form-data when necessary
Merge pull request #151 from gimler/patch-1

fix composer for symfony 2.2
Replaced famfamfam icons with bootstrap ones
Fix render for Symfony 2.2
Update Resources/doc/reference/query_proxy.rst
Merge pull request #168 from silentinet/patch-1

Update Resources/doc/reference/query_proxy.rst
DBALException catch added to batchDelete and delete
DBALException use statement added
Merge pull request #170 from robertdolca/master

DBALException catch added to batchDelete and delete
Trigger event when appending form element
Route name and parameters option added