Add various improvements to docs

[KTibow]

I tried to do a PR to the original (OneDrive#174) but it wasn't being maintained, so I'm trying to push it here.
(I know it was a fork of the original. I had already done my changes, so I did a PR from your repo to my repo before starting this PR.)
Improvements:

• Add source of client secret and ID (https://github.com/AtakamaLLC/onedrive-sdk-python/pull/3/files#diff-04c6e90faac2675aa89e2176d2eec7d8R36, handy for beginners)
• Change code formatting to python3 and change raw_input to input (because python 2 is deprecated)
• Add examples for selecting item by filename and deleting an item (https://github.com/AtakamaLLC/onedrive-sdk-python/pull/3/files#diff-04c6e90faac2675aa89e2176d2eec7d8R136-R141, https://github.com/AtakamaLLC/onedrive-sdk-python/pull/3/files#diff-04c6e90faac2675aa89e2176d2eec7d8R189-R197. I'm being redundant about the deletion because if they copy and paste the code into an editor they still have a warning. Why would you want to delete something? If you're backing up something, then you probably want to save space on your OneDrive by deleting the old backups.)
• Add example for async upload progress (https://github.com/AtakamaLLC/onedrive-sdk-python/pull/3/files#diff-04c6e90faac2675aa89e2176d2eec7d8R232-R240)
• Mention CLI interface (https://github.com/AtakamaLLC/onedrive-sdk-python/pull/3/files#diff-04c6e90faac2675aa89e2176d2eec7d8R277-R279)

This should help people who are new. By the way, why is this repo called onedrive-sdk-python instead of what it's called on pypi, onedrivesdk-fork?

[earonesty]

I'll see about changing the name. Not sure we can without splitting from the original.