Adds show / hide delay

[nicysneiros]

This PR adds tooltip-show-delay and tooltip-hide-delay attributes do the directive. These attr expect a number value expressing the delay time (in milliseconds) to show / hide the tooltip. The delay is implemented by adding $timeout to the function that adds / removes the class "active" to / from the tooltip. The readme is updated with these attributes.

This PR solves issue #153.

[45kb]

Hi @nicysneiros this is a stunning work you've done.

Only the problem is $timeout, which is too much heavy (specially if you are using multiple tooltips on a page).

As you can see in the CSS file, there are simple classes that applies fade effect on tooltip, so delays should be done via CSS animation delay and not via $timeout 👍

If you can make this changes we we'll merge it, thanks!!