#316 Add --do-not-minimize option to hfst-regexp2fst

[sjurum]

Would it be possible to add an option to NOT do implicit minimisation in hfst-regexp2fst? As it is now, minimisation is done automatically and unconditionally AFAICS, and that blows up certain fst’s, especially error models for spellers. The error models are pretty simple from a regex/fst point of view, but minimisation is doing the opposite of the intention for them - making the fst's huge instead of smaller. It also slows down compilation quite a bit