Implement command: add

[rmamba]

This is where users need to be able to decide what to do with their local data. Also need to be able to decide what to do with conflicts.

possible scenarios:

• [x] new local file
  • it's not in local content.json file
  • it's not in S3 content.json file
  • does also not exist in S3
• [x] updated local file
  • it's not in S3 content.json file
  • does also not exist in S3
  • but it is in local content.json file

For each of this options user needs to decide what to do. First two are simple. It needs to write them to local content.json file. When user makes a push it will be UL to S3.

Last two are a bit more tricky. User can force updated file to be UL to or DL from S3

[rmamba]

make this command list differences between local folder and content.json if you don't specify a file after add. Maybe this was not clear from the description above.

List:
sss3.py add

Add/Overwrite file:
sss3.py add newfile.jpg

@lolceh

[rmamba]

Added tests and logged bugs