Canvas object now provides fps
fixed line length mistake
Added explanation of fps update in canvas
Added measure_fps with window setting and callback functionality
Fixed Timer initialization
Fixed whitespace and indent errors
Passing None callback to measure_fps turns it off
Update is called after every window specified by measure_fps
Fixed timer import error
Fixed coding standard mistake
Fixed coding standard mistakes
Added example for fps
Merge branch 'hacks' of https://github.com/mssurajkaiga/vispy into mssurajkaiga-hacks
Merge branch 'mssurajkaiga-hacks'
+ minor edits
New scikit-image theme for docs.

Should fix an error related to Debian packaging.
Maybe also fixes issue #112?
create a pyopencl context shared with vispy... 
try to share objects as well