Minor changes and bug fixes

[aricneto]

• Removed the "Rate this app" dialog
• Added a "Contributors" button to the "About" page
• Updated support libraries
• Changed color picker library since previous one wasn't working with the new support libraries
• Fixed a bug that prevented the user from stopping the timer while a scramble was being generated
• Fixed a bug where stats would not refresh when puzzle or subtype were changed

  Moved the creation of the statistics loader to a function that gets called whenever the puzzle or subtype are changed. It seems to be leaking memory but I haven't found another way to fix this.