o.c.display.pvtable: Check file extension for SaveAs
o.c.display.pvtable: Store saved value as text

.. because that's read and written to the files, while PV type may be
unknown.
o.c.display.pvtable: Fix (new) comparison

OK for double, enum, string, short
o.c.display.pvtable: Display current value for numeric arrays
o.c.display.pvtable: Extract SavedScalarValue..
o.c.display.pvtable: Add SavedArrayValue. Takes snapshot and compares..
o.c.display.pvtable: XML format handles arrays
o.c.display.pvtable: Autosave format reads/writes arrays
o.c.display.pvtable: Display ASCII byte array as string
o.c.display.pvtable: Support restoring arrays
o.c.display.pvtable: Add file comparison tests
o.c.display.pvtable: Add changelog, inc. versions
o.c.display.pvtable: Allow entering new values, writing to the PV.
o.c.display.pvtable: Move older history info to changelog
Update feature.xml
Update pom.xml
Merge pull request #750 from ControlSystemStudio/bug748

PVTable Update: Handle arrays, allow editing