Tiny typo fix
Recognize haskell test files
Update README.md

Update in case homebrew fails when installing Go.
Version 1.0.0
Define a demo directory

If you are not logged in, there's no way to know where you want to
download sample files to. A subdirectory under the current working
directory seems reasonable, and it's easier to move the result around or
delete it (because each language gets a subdirectory under that).
Optionally allow demo when not logged in.

If no config is found, create a demo directory in the current working
directory, and download the assignments to it.

This needs refactoring, but I don't know Go well enough to do that yet.
Print out fetched assignments.
fix submit with relative path name
Update README
Bump version: v1.0.1
Refactor error handling in demo command
Add missing assertion in demo dir test
Clean up config
Refactor api methods to take Config objects
Remove dependency on `errors`.
Simplify error statements
Print errors using default format
Refactor API fetch method

* tighten scope of structs
* remove unnecessary pointer
* introduce pernicious returns
* remove unnecessary assert
One folder to rule them all.

* Inline all the files into the project directory.
* Get rid of `src`.
* Use `go get` for dependencies.
* Make build scripts work.
* Update README with new requirements/instructions.
Add go get to Travis config