BootstrapTable renderer fixes

This pull request contains a few small fixes for the bootstrapTable renderer:

* Have the renderer respect the columns isRowClickEnabled property (all columns where being formatted as links)
* Use array sum instead of array merge to add the empty option in the setFilterSelectOptions, otherwise it will change the array indexes if a numeric array is passed (i.g. array(1 => 'Low', 2 => 'Medium', 3 => 'HIgh'))
* Use strict comparison when checking the filterActiveValue, otherwise if we have a select option with value '0' it will be selected when the value is ''