TODO:

* see if we can add more stuff from recent perls

* see if we can implement sv_catpvf() for < 5.004

* add hv_stores() to blead

* Andy's SvREFCNT_inc patches?

* MULTICALL ?

* improve apicheck (things like utf8_mg_pos_init() are
  not currently checked)

* more documentation, more tests

* Resolve dependencies in Makefile.PL and remind of
  running 'make regen'

