Refactored pandas_timedelta_to_timedeltastruct
this mostly cuts down on copy paste, but also implements `const` where it can be done on some variables
Small question, otherwise looks like a nice cleanup This pull request is stale because it has been open for thirty days with no activity. Please [update](https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#updating-your-pull-request) and respond to this comment if you're still interested in working on this. Sorry I let this slip - this should be reviewable now Thanks @WillAyd 