move remaining core.tools.timedeltas to tslibs.timedeltas

[jbrockmendel]

Moves remaining contents of core.tools.timedeltas to tslibs.timedeltas. Several can be cut/paste directly. A few changes were made in moving _convert_listlike and to_timedelta up into tslibs.timedeltas.

• instead of using is_list_like (not implemented in cython), directly exclude str-like case and then check hasattr(arg, '__iter__').
• instead of using is_timedelta64_dtype(arg), check that arg is an ndarray and then use arg.dtype.kind == 'm'. Analogous for is_integer_dtype.

Updates imports.

[jreback]

instead of using is_timedelta64_dtype(arg), check that arg is an ndarray and then use arg.dtype.kind == 'm'. Analogous for is_integer_dtype.

these are pretty non standard and would like to avoid

[jreback]

i don’t think a whole lot of value of moving a top level api like this

what is the motivation?

[jbrockmendel]

Yah really just unification at this point. For me its a coin-flip as to whether its worthwhile.

[jreback]

i prefer to leave self contained to cython or really perf sensitive

python is much easier to debug for most folks

so either close or strip out to minimal changes

also instead of going to new areas can work in trimming the existing list?

really appreciate all things!

[jbrockmendel]

these are pretty non standard and would like to avoid

Prefer a runtime import of the non-cython funcs?

[jbrockmendel]

also instead of going to new areas can work in trimming the existing list?

Ha fair enough. Will close now, may revisit down the road.