Update mecab-ko-dic to 1.6.1-20140814

Updated mecab-ko-dic to 1.6.1-20140814. Also removed the caveats editing config manually and added a shell command to do it automatically instead.
I agree with doing it in Ruby but I didn't want to overwrite an existing custom setting of a user every time the formula is updated, just in case.  That's the reason I tried to add it only if "^dicdir.*=" does not exist.

If we want to do it in Ruby, would you please advise one in Ruby with the same logic, since I am not familiar with it?