Refactor Selection to break out individual handlers and allow new ones
Fix regression during Selection refactor involving right-clicks

Interestingly this was not observable on Mac OS X where initial testing
was performed, but on Windows it was readily apparent.
Add buttons to Selection.html to test new toggle mode for touch input
Document Selection handling refactor in CHANGES.md
DnD: mix in Selection to guarantee more resilient drag handling
Document DnD inheriting Selection in CHANGES.md
Passing value through when selecting via `toCell`

When using the `toCell` parameter, it's not properly passing the
`value` argument through to the cell selections, so deselection
doesn't reliably work. This simple change looks to fix that.
Merge branch 'cellsection-tocell' of git://github.com/brianarn/dgrid into deselect-range
Also fix range deselection in Selection
Document Selection/CellSelection range-deselect fixes in CHANGES.md
Selection: change handler naming pattern to _<mode>SelectionHandler
Removing unused variable

This variable was once in use, but is no longer, and is causing errors
in touch-based environments that aren't webkit.
Merge pull request #493 from brianarn/webkitconvert-fix

ColumnResizer: remove unused variable
Fix #474: Update body scroll position when a header cell is focused
Fix #492: Use user-select: -moz-none in FF to allow selection in inputs

This only affects FF until 21, at which point none will behave the same
as -moz-none, according to MDN.
(https://developer.mozilla.org/en-US/docs/CSS/user-select)
Fix #494: make Keyboard more resilient against structure resets