* Add manpage
Adds a basic manpage that was autogenerated with `help2man` and then
slightly adjusted with information from the README.md and better
formatting.
* Add zsh completions
Add completions for the zsh shell. These should be complete and even
allow completion of the command inside `--command` and `-e`.
* Add bash completions
The bash completions are almost on the same level as the zsh
completions. The only little thing the bash completions do not do is
complete inside of `--command` and `-e`, instead bash just stops
completion after these options.
* Update readme with manpage and completions
Added the install instructions for the manpage and completions to the
README.md.
Also tweaked the current readme a slight bit because the build section
was structured in a slightly confusing way.
