Button: fix when inside ButtonSet
Grid_Advanced: allow to pass options
QuickSearch: features & fixes

1) Implementation of "cancel" button (backwards compatible)
Can use it if call QuickSearch like this `$grid->addQuickSearch(array('name'),'QuickSearch',array('show_cancel'=>true));`
2) Buttons moved inside ButtonSet. This allows nicer CSS styling.
3) You can now also pass comma-separated values (string) of fieldnames when initialize QS.
Like this: `$grid->addQuickSearch('name,email,phone');`
Button: fix functionality in buttonset

Now it allows to pass options to JS button also if it's inside buttonset.
ButtonSet: allow to pass options to Button

1) Now allows to pass options to Buttons.
2) Now allows to pass options to JUI buttonset().
QuickSearch: feature

Show cancel button only if it's enabled at all and if particular filtering is enabled.
Filter: documentation
QuickSearch: documentation
Merge pull request #273 from DarkSide666/patch-5

QuickSearch: features and fixes