mark .box-shadow() mixin as deprecated

BS3 commits: 16fd8cd01e73a4370b4370e42b627554c0b6cbcd
docs & comments: v3.1 => v3.1.0

BS3 commits: 1a36e4fa1e9d9220a242d01062941a16ef07e660
Change positioning reference from left to right in affix's example.

BS3 commits: 72a31db2100246224306ce9c6cd376de76a2b80b
document id requirement in carousels per 12393

BS3 commits: e08e871f01fd8848101e152c9afdd758280de27d
Do npm caching based on npm-shrinkwrap.canonical.json

BS3 commits: 50ad304bb52b344828352e888b6f8ddc042ba176
grunt dist