Adds support for np.datetime64 and strings with timezone info

[ankitkmr]

This offers a solution to the issue #798

[ankitkmr]

@dpshelio Finally added support for np.datetime64 input which I guess the issue was about in the first place. Also added support for input strings with timezone information. Added (some important to this issue) Test Cases that are supported. Also solved the problem of possible multiple '-' in time_string

[dpshelio]

@ankitkmr why did you closed the other PR? You could have just updated it... Well, my comments from #1343 still apply here, e.g., there is repetition in the code that should be reduced.
The tests have to go in the tests files and using pytest. Check SunPy's dev documentation for more details on how to do it. And please, update the pull request by updating the branch where you are doing the changes, not closing and opening a new one each time.

[ankitkmr]

@dpshelio Umm sorry I couldn't figure out back then that I could simply commit and update that PR in itself. It wont happen in future. As for the repetition, corrected.
And yeah I'll do the test cases sorry didn't know that thats how its supposed to be done !! in the meanwhile I made up the blog let me know if its ok !!

http://home.iitk.ac.in/~ankitkmr/blog/

[ankitkmr]

@dpshelio OK I condensed it even more I agree too much useless code there !! Oops..I added the tests as well according to the dev guide. They can be found in PR1345 (new PR) this I guess happened because I was committing to a new file.

[dpshelio]

No, they are not in a different pul request because you've made changes in different files, but because you made the changes in a different branch. If you do it in the same branch you would see it here.
I would suggest you to close the new PR #1345 and cherrypick the commit you did into this branch ankitkmr-patch-3

So, probably you could do (I've not tested it):

$ git checkout ankitkmr-patch-3
$ git cherry-pick 1821096
$ git push 

[ankitkmr]

@dpshelio Done !! Now I think I am moving on to writing my proposal !!

[wafels]

As written, the code requires timedelta to be imported explicitly in order for this PR to pass.

[ankitkmr]

Thanks @wafels just noticed that and added its import to the test_time.py file