Standardize time format

[angerhang]

Currently, there are many different kinds of time formats being used at various places. Their corresponding time format strings are hard-coded in place which makes it more difficult to maintain and make changes.

Ideally, move all the time format string into a macro file.

[smallsr]

Along these lines, is it possible to add clarification in accProcess.py -h as to the date format on --endTime and --startTime? It is unclear in the example 1991-01-01T23:59 which entry is the month and which is the day. Perhaps a change in example to something like 1991-12-25T23:59 would be sufficient?