Split letters in articles titles for crossword search.
- Add 30 columns, each for a single letter in the order of the title (ascii version).
- Those can be used to efficiently find words with only a few hints anywhere in a word
with a set length.
- Set this as an arg from the command-line (to stay compatible with earlier DB)

Change-Id: Iba64bac0f221bcea849895f5a27f57eee33bd91e