Consolidate some of the DateTime-Period arithmetic methods.
Clean up io code. In particular, fix the vectorized Date/DateTime parsing methods as well as format().
Move toms() methods to period.jl since they're Period methods. They're also now used in arithmetic.jl
Change StepRange iteration for TimeTypes so that it's r.start + r.step*i instead of incrementing the state each time. This allows a step of Month to be more intuitive.
Cleanup the types.jl file a little. Make precision return a Period for Date/DateTime
Test updates
General clean up of code comments, formatting, minor tweaks here and there.
Merge branch 'master' of git://github.com/quinnj/Dates.jl