added pickle method for quantity
added test for pickleability of quantity.
added is comparison and some pep 8 changes.
autopep8ed
Perform bounds adjustment in the native unit.
Add a test for loss of precision in bounds check
Round up if any of the fields overflow due to low precision
un-autopep8ed the URL as to @astrofrog's request
un-autopep8ed another URL as to @astrofrog's request
un-autopep8ed another URL as to @astrofrog's request
Merge pull request #1325 from wkerzendorf/units/quantity_pickleable

Make Quantities pickleable again
Further refine the rounding up algorithm.
Merge pull request #1311 from mdboom/coordinates/loss-of-precision

Angle bounds checking loses too much floating-point precision