Add data for Tagalog

[ikalchev]

This adds data for a tagalog stemmer (See snowballstem/snowball#273). I will submit a PR for the Tagalog stemmer shortly.

[ikalchev]

Thanks for the review, I guess I missed the case folding from the instructions.

[ojwb]

I've pushed a commit to address a couple of things:

• there were 57 duplicate words in voc.txt
• we've found sorting voc.txt in ascending byte order is best as it gives a sort order which doesn't depend on locale settings, which makes it easier to do ad-hoc scripting, etc