Making a clickable interface for running scripts on any OS

[target for this is post-0.10]
This is dependent on #323 (awesome~~~) and addresses #235 and an issue I can't find.

Background:
* KA Lite administrators need not be technical people.  Many do not know how to open a command shell in their OS.

Issues:
* Most of our documentation assumes that they could open a shell, change directories, then open a command.
* Running management commands can be dangerous--we should have a way to "sandbox" things, as much as possible.

Suggestion:
* All of our top-level scripts (install, start, stop) should be double-clickable on all OS
* We should expose management commands to users through a double-clickable interface, with as much sanboxing as possible.

Changes:
1. Create .command files, that make install, start, stop double-clickable on OSX
2. Make sure that install.bat and install.sh don't use relative paths (and so are double-clickable)
3. Add a management command that allows "sandboxed" running of management commands
    * Gets input from the user (this is what we put in our wiki doc; it's a management command with args)
    * Makes sure they're running one of our "allowable" commands
    * Runs the command

Testing:
* I did not test run_command.bat on Windows.  Please test!
* I did test the management command scripts, and everything on OSX.