Rendering Actions column in grid is optional closes #311

In case there is no TH with actions class,
no action cell will be rendered. Othrewise will be.
Merge branch '311_Actions' into next-0.6
Added extended filtering fixes #310

By default extended filtering is applied on date,
datetime and number fileds.
Merge branch '310_Extended-filtering' into next-0.6
Merge branch 'next-0.6'
0.6.0