Integer+fractional day implementation, using double-doubles.
Tests adapted as well.
PEP8 fixes for time
Improve precision code docs and use more meaningful var names
Add more tests of precision code
Move precision tests to test_precision, refactor into separate tests
Add discussion of floating point accuracy to Time documentation
Merge pull request #1 from taldcroft/time-int-frac

Add new tests, clarify code, and do PEP8 fixes
Merge pull request #1189 from mhvk/time-int-frac

Update internal time manipulation for consistent sub-nanosecond precision