docs(tooltip): fix show/hide event names

The events description for modal is also fixed

fixes #1032
docs(dropdown): properly document both directive and service usage (fixes #884)
fix(select): multi-select checkmark icon now displays correctly in Firefox

The bootstrap dropdown > li > a white-space: nowrap; setting seems to cause a display bug for the checkmark icon in Firefox. I got it to display correctly by moving the icon element outside the anchor element. Maybe there is a simpler way for fixing this?

fix for #735