Units that don't derive from float
Add ValueArray
Fix to setitem for valuearray
Documentation.  Move shared methods to WithUnit, fix to setitem
__eq__ never raises exception.  Bug fixes.
more tests for units.py
Added tests for ValueArray
Simplified ValueArray tests
Run test_types.py as main, and import from source dist rather than installed copy.
Added test for Value specified with 'None' units, which fails
Make dimensionless stuff turn into base object
Only mutate path if run as script
Merge branch 'new_units' of https://github.com/martinisgroup/pylabrad into new_units
Change array asserts to use assertTrue
Change value to _value.  Fix bug with deprectated None unit
White space
Removed broken imports accidentally included in previous commit
Merge branch 'new_units' into GPIB