no more tags in cells

Arbitary length sequence support on stack dropped. Vector data will
always be in-mem, and referenced directly by address.  GC will be
necessary to reclaim anonymous data.
documented size defines
better naming of helper macros
beginnings of dictionary
fixed header deps in rakefile
two-arg form of DICT
partial Revert "fixed header deps in rakefile"

This reverts commit 6bcaaad82d28af34ca19be5673a0ea6dffc761b0.
made peek more general
endsub -> retsub
truefalse (aka "?") seems to work
agenda