fix #12143
make customizer compilation code more generic
have customizer output Bootstrap Theme too; fixes #12003
grunt dist build-customizer
adjust filename to indicate that customize JS is minified
enable CSSLint in test suite; fixes #12094
bump grunt-contrib-less to v0.9.0
Merge pull request #12149 from twbs/bump-grunt-contrib-less

bump grunt-contrib-less to v0.9.0