improve known_hosts font-lock (from M-x man authorized_keys)
add authorized_keys font-lock rule.
fix duplicated hook variable name
add comment and README doc.
improve font color integrity.
add new keywords and fill list
Merge pull request #1 from mhayashi1120/fix-font-lock

Fix font lock
Merge pull request #2 from mhayashi1120/add-new-keywords

add new keywords and fill list
Make ssh-config-font-lock-keywords be case insensitive.