Add interactive compilation

[jyn514]

Judges noted in final this was similar to Jupyter Notebook. Let's go all the way and support dynamic recompilation. In other words, add editing, feed the text to a compiler/interpreter, and show the output.

For now, we can use makesnap.sh and runsnap.sh to compile and run respectively.

[jyn514]

Just thought of something - since we don't need git snap to make zip files anymore, we could use it to compile and run things in history, i.e., git snap HEAD~1 -- test.py. It would also allow a client/server model where the front end just runs git snap $COMMIT $FILE and shows the output.

We'd implement this with a git alias: git config alias.snap "\!$(git rev-parse --show-toplevel)/<script>"

[jyn514]

If we do add editing on a git branch, we'll need some way to save the files. I think git stash is the best way to go; that way it doesn't slow down switching branches but still has the changes for later. We could maybe ask the first time if the file should be discarded or not.