Merge bidixes into a multidix

Merge contents of:

1. `apertium-turkic/apertium-kaz-tat.kaz-tat.dix`,
2. `apertium-turkic/apertium-kaz-rus.kaz-rus.dix`,
3. `apertium-turkic/apertium-eng-kaz.eng-kaz.dix`,
4. `apertium-turkic/apertium-kaz-tur.kaz-tur.dix`,
5. `apertium-turkic/apertium-tat-rus.tat-rus.dix`,
6. `apertium-turkic/apertium-tat-eng.tat-eng.dix`, and
7. `apertium-turkic/apertium-tat-bak.tat-bak.dix`

into `divan.dix`. Delete lines which were copied over until bidixes are empty.

Adjust `bak.lexc`, `tat.lexc`, `kaz.lexc`, `eng.dix`, `rus.dix` and `tur.lexc` if necessary as you go.

Generate bidixes from `divan.dix`. Run a corpus test comparing performance of translators before and after.

Also see:
- apertium/apertium-kaz#11
- https://github.com/taruen/apertiumpp/blob/master/dev/wordgraph.py