1. add swiftype as a search option, use SWIFTYPE='(SWIFTYPE_KEY)' to enable it. swiftype search has higher priority than google custom search
2. since there are some lag problem in some area of cloudflare service, some files switch to bootstrapcdn
changed external link icon
fixed some icon problems
Merge branch 'master' of github.com:KenMercusLai/plumage