Settings: SlimPIE second layer (2/2)

I promissed yesterday to stop working on SlimPIE....but due
team and user whishes I decided to do a last tweak so that
all are happy.

This commit introduces the following:
- enable second buttons row
- up to 7 buttons + 7 longpress buttons
- usual customizations on that buttons
- means it is possible to add 5 + 5 on first row and 7 + 7 on second row
- resource friendly...reusing most of present code
- new introduced observer for second row is just
  observing when second row is really enabled
- due optimizations we can hold the speed and responsive we
  introduced yesterday on same level
- reduce default size back to 1
- some minor changes

Now SlimPIE is finished

Screenshots (first shows default values for first and second row):
https://dl.dropboxusercontent.com/u/106208842/Screenshot_2013-05-01-02-30-47.png
https://dl.dropboxusercontent.com/u/106208842/Screenshot_2013-05-01-02-36-25.png

cheers

Change-Id: Icac694022e051eb3ced986829f7196798c958b8e