more state, edge suppression

* More epsilon removal when optimizer can steal from singleton states.
    (Completely stolen singleton states are removed.)
* Fates that point to other similar fates are treated as epsilons.
    (Also, don't create fates we know are dups in the first place.)
* Duplicate edges are now removed from any given state.
* Now extends the remap array correctly.
* Now relies on autozeroing rather than duplicating array zeroing already
    provided by VMs.
* Now copies to new state array rather than reusing old one, so reclaimed space can be GC'd.
* Gave NQP its own NQP_NFA_DEB env var, distinct from MVM_NFA_DEB, since not all
    NQP is MVM, and sometimes you just want some of the debugging output.
* Added vim modeline.