MNT: some PVPositioner fixes for motion status
MNT: use _move_changed
ENH: limits on EpicsSignals and Positioners
MNT: fix method names (see comments on PR #26).
Merge pull request #27 from NSLS-II/pvpositioner

ENH: PVPositioner improvements
Merge pull request #28 from NSLS-II/limits_fix

ENH: limits on EpicsSignals and Positioners (issue #25)
MNT: bump log-level on connection handler.
ENH: use ipython StoreMagic to persist a _scan_id value.


Relies on setting 'c.StoreMagic.autorestore = True' in profile config.
Merge branch 'master' into cas_test