more organised style guide for homework; add bunch of scripts

`generate-report` generates a template Edmodo assignment report.
`start-rec` simply starts a floating `urxvt` session with correct
geometry (80x24) in i3, to use `ttyrec` in.
`gifscript` converts a `ttyrec` file to an animated .gif image.
`start-gs` invokes `gifscript` in a new 80x24 floating `urxvt` session
so it's recorded properly.
more style-guide; alter homework 1 to use style-guide
remove length from assignment.md