BaseGrid.set_filter Should Take More Than One Value

[calebsyring]

Here:

webgrid/webgrid/__init__.py

Lines 735 to 737 in 0d27fec

	def set_filter(self, key, op, value):
	self.clear_record_cache()
	self.filtered_cols[key].filter.set(op, value)

we should handle the case in which we might want to pass into multiple values to filter.set, like if we were looking to do a between operation.