Update jQuery form plugin to v3.45.0

Fix #868
Fix #1729
Restore IE workaround 

https://github.com/sonata-project/SonataAdminBundle/pull/1797#issuecomment-28623826
Merge pull request #1797 from Maks3w/patch-3

Update jQuery form plugin to v3.45.0
Added tests for Admin methods: getRoot, getRootCode, setPersistFilters, getExportFields
Merge pull request #1804 from pulzarraider/admin_test2

Added tests for Admin methods: getRoot, getRootCode, setPersistFilters, getExportFields
Merge branch 'sonata/master'