interfaces added, test empty set
added internal methods
rounddate added
noround test added
set internal
get test fixed
byteset returns len
shiftoffset failing test added
shiftby function added to byteset
shiftoffset fixed
Merge branch 'master' of github.com:advincze/golang-travl

Conflicts:
	src/travl/byteav/byteav.go
	src/travl/byteav/byteav_test.go