Update DefaultPrefs.json
Case insensitive matches, reload prefs, and can set valid extensions to all.

-Matches are now case insensitive.
-Prefs are now reloaded in findUnmatchedFiles() to make sure we have any changes.
-Can now set valid extensions to ALL to list all files except those in the ignore lists.
Update changelog.txt
Merge pull request #47 from srazer/master

Case insensitive matches, reload prefs, and can set valid extensions to all.