isMousePath/Element fix and animateJQP enhancement

core.js
* isMouseInPath and isMouseInElement previously broke if the location of
  the Elroi element changed; this was a result of the element offset
  being cached. The offset is now determined dynamically using the
  getRelativeMousePosition method.
* Added stopJQP method which provides a way to stop an element and reject
  the promise generated by animateJQP.  Previously if animateJQP wasused
  the promise it returned would remain in limbo if a call to stop()
  was made.
Merge pull request #9 from gsmith85/promise-fix-and-mouse-in-path-fix

isMousePath/Element fix and animateJQP enhancement
Merge pull request #10 from ahahn/master

customizable y-axis label formatting
New pie wedgeEventsEnable/Disable implementations

- The wedgeEventsEnable and wedgeEventsDisable methods now increment and
  decrement a counter.  When the counter is 0, mouse events are enabled,
  otherwise they are disabled.  As a result, multiple calls to
  wedgeEventsDisable require a matching number of calls to
  wedgeEventsEnable to turn wedge mouse events back on.  This is useful if
  multiple animations will happen in succession and the goal is to
  disable mouse througouth the entire transaction.
- Simplified generateId method in core.
README clean up

- Removed extraneous 'http://'
- Capitalized Elroi in all cases other than in the filename elroi.js
Merge pull request #11 from gsmith85/promise-fix-and-mouse-in-path-fix

New pie wedgeEventsEnable/Disable implementations