Fix left/right scroll on OSX/trackpad

Speculative change - this fixes left/right scrolling for me.  However
it is entirely possible that it breaks left/right scrolling for other
trackpads that issue wheel events - none of my other devices issue
left/right wheel events (and perhaps such devices are few and far
between).  Submitted to see whether anyone else is impacted.
bugfix(Selection): #1550 selection was removing ui-grid-row class which removed rowHeight from selected row
Merge pull request #1542 from PaulL1/tune_mac_scrolling

Fix left/right scroll on OSX/trackpad
infinite scroll feature

removed

ngdoc added

infinite scroll test fix

testing for infinite scroll fixed and passed

ngdocs, promise function and description added

infinite scroll feature (ngdocs, tutorials, tests added)

timeout removed
Merge pull request #1543 from rem4ik4ever/infinite-scroll

Infinite scroll features
Give infinite scroll tutorial a 'tutorial number'
enableScrollbars in gridOptions