Fixes #139 Search form doesn't submit filters on IE10
Fixes #140 KeyError when using MPTTModelAdmin and SortableModelAdmin
together. Bug appeared due to changes in latest MPTT library.
Looks like get_changelist_form() form variable override is no longer
needed and removing it fixes the KeyError problem.
JS: Sortable JS improvement that fixes empty inline creation when
saving inlines with blank inputs.
Version bump to 0.2.4 and changelog updates
Consider using target=_blank for models as well
Merge pull request #141 from mariusionescu/develop

Consider using target=_blank for models as well
Merge remote-tracking branch 'upstream/develop' into develop