Add Gist & Customizer URLs to customized files & config.json

BS3 commits: 5458134f5e02d377d50ca2fcabe80a75215273c3
use glob instead of fs.readdirSync since /less now has subdirs

BS3 commits: 24c5a453b2314ded0fcdea20dc30f2e02c0cd501
grunt dist

BS3 commits: e8551d4f5027e863cce7e8a6d38ff5086e65c3ea
grunt dist, grunt update-shrinkwrap build-customizer dist

BS3 commits: e8551d4f5027e863cce7e8a6d38ff5086e65c3ea,
b5ae8f9722c0f4a5493e5fb81a53b6dd19d6fdd6
grunt update-shrinkwrap build-customizer dist

BS3 commits: b5ae8f9722c0f4a5493e5fb81a53b6dd19d6fdd6