improve UTC helpers
improve UTC helpers

hzruandd/AutobahnPython,tavendo/AutobahnPython,Geoion/AutobahnPython,iffy/AutobahnPython,markope/AutobahnPython,nucular/AutobahnPython,ttimon7/AutobahnPython,crossbario/autobahn-python,crossbario/autobahn-python,dash-dash/AutobahnPython,claws/AutobahnPython,jvdm/AutobahnPython,meejah/AutobahnPython,bencharb/AutobahnPython,schoonc/AutobahnPython,dash-dash/AutobahnPython,oberstet/autobahn-python,oberstet/autobahn-python,inirudebwoy/AutobahnPython,luhn/AutobahnPython,tomwire/AutobahnPython,iffy/AutobahnPython,mcfletch/AutobahnPython,Jenselme/AutobahnPython,RyanHope/AutobahnPython,claws/AutobahnPython,oberstet/autobahn-python,iffy/AutobahnPython,mcfletch/AutobahnPython,crossbario/autobahn-python,iffy/AutobahnPython,dash-dash/AutobahnPython,dash-dash/AutobahnPython