Add Download feature
deleted binary

Revert version string

Fix documentation for download

Return -e flag for bash

Fix to use filepath.Join

Replace switch..case for argument check

Fix download usage msg and empty line in error handling

Replaced tab to space

Fixed upcoming change for json (problem, solution)

Renamed UserName to Username for consistency

Fixed use of change "Username"

Shorted for loop to deal with key and value

Named key and value variable

Fixed key, value error

Change to ProblemFiles and SolutionFiles

Changed bin/* files back to permission 755

Post pull request fixes
Merge branch 'backup' of https://github.com/EECE-310-14-Project/cli