fix attr to val() and replace timer with events

attr is no longer supported by jQuery 1.9 as it's incorrect to use
attr to get value for a textarea.  val() should be used, instead.

also, removed the timer that fires every 10 milliseconds
and instead implement event-based firing
timer is replaced by: keyup change input paste

tested in chrome, ie8, firefox
add safety code to avoid multiple initializations
Merge pull request #5 from Leonidaz/master

fix attr to val() and replace timer with events
removed onfocus event handler