Unit between color/text and colorbar became corrupt when changing time step

[Angus Yeh]

When viewing production/transient results (either h5 or listings), change time step will corrupt the unit between scene color/text and the associated colorbar.

[Angus Yeh]

Actually when user set model limit, if the unit has been changed from default to something new, it will also cause limit values to be wrong.

[Angus Yeh]

Fix issue #110, units corrupt between scene color/text and colorbar when change time step.

→ <<cset 612945e0b858>>

[Angus Yeh]

Fix issue #110, units of colorbar limit wrong when not using default unit.

→ <<cset 0b923757c3e1>>

[Angus Yeh]

Fix issue #110, unitChoices() failed to accept unit strings that are already pint.unit.Unit.

I wasn't sure that this was part of the issues #110, I had trouble reproducing the error, but looking at the .log file I noticed that it sometimes have trouble when calling unitChoices().

→ <<cset a05a932f068a>>

[Angus Yeh]

Fix issue #110 when some unit passed into routine is not a string.

Resolve some issues (still unable to reliably reproduce) with "AttributeError: 'Unit' object has no attribute 'replace'".

→ <<cset cf6cbe793083>>