minor format fixes
Merge branch 'master' of github.com:CherryKerry/browsertrust-extension-firefox

minor format fix
Added server connectivity function to check when adding a fingerprint
server. Modified shouldFingerprint function in Engine.js to allow for
excluding content to fingerprint based on wildcards e.g *.jpg in
exclusion file will now exclude all .jpg files from being fingerprinted.
Fixed off by one bug in substring call in BTrust.js. Getter and Setter
functions for modifying trust server URL in preferences. Added to Tests for above.