Add some info about bitvec
Add some info about bitvec

sschnug/pyeda,cjdrake/pyeda,GtTmy/pyeda,GtTmy/pyeda,cjdrake/pyeda,karissa/pyeda,pombredanne/pyeda,pombredanne/pyeda,sschnug/pyeda,cjdrake/pyeda,karissa/pyeda,karissa/pyeda,sschnug/pyeda,pombredanne/pyeda,GtTmy/pyeda