add alexaboostup.com and alexamaster.com
match filtered out file extensions only at end of files, ignore vim swap files

This should be more robust, should a future front domain happen to contain
substrings like .py or .txt.  Also, vim swap files in the local directory would
cause a weird YAML error when certstotemplate.py tried to feed them as certs.
Merge pull request #30 from getlantern/cn-alexa-sites

Cn alexa sites