Implement remote copy; some integration test modifications

[eddiekelleypdx]

Implemented 'cp' command to perform remote copy using only SFTP commands; Implemented 'cp_r' command to perform remote copy using SSH/bash commands; Added cp and cp_r integration tests; Added chmod invalid integer integration test; Added shebang and imports for running unit tests as script; Removed TODOs in integration tests, and implemented setUp and tearDown for ls and chmod; Closes #27

• [ ] The copied directory should contain a copy of all files and folders contained within the source
• [x] The copied directory must have a different name from the source directory if it is copied into the same location
• [x] A non-existent directory cannot be copied

[eddiekelleypdx]

Good catch... I can confirm that the cp command isn't working the same way as cp_r, and have a potential fix created... The more worrisome part is why the integration tests (specifically, the walktree test) wasn't failing.

[eddiekelleypdx]

I've modified the cp command to work more like cp -Rp does, and it appears to be working as described...

Unit and integration tests for cp are working normally, but there are a couple of errors being reported when running other tests (that expect a Downloads directory to exist on the remote SFTP server, but aren't creating it). After creating that remote directory, tests are passing normally.