tweak style of 'search'box in dropdonws

change 'width' of search box in the dropdowns which uses 3rd party plugin for implementation.
Merge branch '73183568add-dropdown' of github.com:gengo/style-guide into 73270894buttons-dropdown
add grunt-scsslint
fix scss lint errors
fix compass %extend issue
Merge pull request #19 from gengo/add-scsslint

Add scsslint
format scss files below,  via csscomb

- _button.scss
- _dropdowns.scss
- docs.scss
format scss files below , by using SassBeautify

- scss/_buttons.scss
- scss/_dropdowns.scss
- scss/docs.scss

SassBeautify is plugin for sublime text
https://sublime.wbond.net/packages/SassBeautify
add new sass variable

also format '_variable.scss' by using SassBeautify
apply sass variable '$dropdown-border-radius' in some property
'$dropdown-border-radius' is used in '_dropdown.scss'
change format in several scss files
- change indent level from '4' spaces to '2' spaces
- scss/_buttons.scss
- scss/_dropdowns.scss
- scss/docs.scss
revert 'scss/_variable.scss'
fix conflict in merge

fix 3 conflicts in merge with master

- scss/_dropdowns.scss
- scss/_buttons.scss
- Gruntfile.coffee
fix scsslint error

modify 3 scss files
- scss/_buttons.scss
- scss/_dropdowns.scss
- scss/docs.scss
add grunt task 'concat'

task 'concat' is for concatenating 2 files
- docs.css
- docs.min.css
change to load css files that are used only for github pages

This 2 files are concatenated into 'css/docs.all.css'
- css/docs.css
- css/docs.min.css
fix gh-pages auto deployment

add "bootstrap-multiselect" into "bower.json" as required package
tweak css of docs.css
update setup.sh

add "bootstrap-multiselect" as required packege
fix conflict in merge with 73270894buttons-dropdown

modify 2 files below for merge
- scss/docs.scss
- Gruntfile.coffee

also modify 'scss/_tables.scss' for passing scss-lint