fixes Bug #3569

On packages that uses row_helper when user clicks on add or delete button, the page scrolls to top.
It seems something with ajax
http://stackoverflow.com/questions/1061580/jquery-click-on-anchor-element-forces-scroll-to-top

A simple return false after jquery action fixes the unwanted scroll.
Merge pull request #1053 from marcelloc/patch-1
Correct typo on function name that has slipped unnoticed. Reported-by: https://forum.pfsense.org/index.php?topic=74688.0
Bump to 2.1.2-PRERELEASE since 2.1.1 was released
Make extra sure that we do not start multiple instances of dhcpleases if, for example, the PID is stale/invalid and there is still a running instance.
No pre release this time
Use an alphanumeric test rather than purely is_numericint because the ID is generated by uniqid and is not purely numeric. Fixes #3591