Update bootstrap-chosen.less

replace dpi with dppx
Update bootstrap-chosen.scss
fix division on less
move more border rules to variables
allow customizations to the focus border
remove the choice gradient
Merge pull request #39 from w33ble/border-width

Move more border rules to variables
Merge pull request #40 from w33ble/no-choice-gradient

Remove the search-choice gradient
Merge pull request #37 from hernandev/master

Fix division on less
Merge pull request #35 from piscis/master

Including stylesheet leads to warning in latest chrome
Merge branch 'master' of https://github.com/alxlit/bootstrap-chosen

Signed-off-by: Junliang Huang <i@jhuang.me>

Conflicts:
	bootstrap-chosen.less
	bootstrap-chosen.scss