fixed #210

when the cell editor is set to multiple: true, set an automatic height
the multi-select control so it dispalys more than just 1 line
fixed #258

IE10 (as part of its browser defatuls style) adds in its own padding to
input boxes, which casued the content
to get pushsed down
fixed #262

adding a new property to Backgrid.Column called `sortType`. based on
this value, clicking on the column header will do one of the following:
- "cycle": (default) cycle beween `ascending`, `descending`,
     and default
- "toggle: clicking on the colum header will toggle the sorting between
`ascending` and `descending`

this only has effect if sortable = true
Revert "fixed #262"

This reverts commit 38859c7ce7fcb39fb7de7450adc6a8e748318556.
Merge pull request #272 from morficus/master

Fix #210 (cell too small for multiple selection cells) and Fix #258 (cell padding too thick on IE 10)