EDITOR support.

When running shell commands from Lively that invoke EDITOR (like git commit
without specifying a message), a lively text editor will be used for editing
the file passed to the invocation.

You can also use Lively as your default EDITOR:
1. In your ~/.bash_profile or equivalent setup
export EDITOR=$PATH_TO_LIVELY/bin/lively-as-editor.sh
export L2L_SESSIONTRACKER_URL=http://localhost:9001/nodejs/SessionTracker/connect
alias edit=$EDITOR

2. When a command invokes $EDITOR or you run edit filename.xxx a text editor
will appear in the last active world that was started from the sessiontracker
specified in L2L_SESSIONTRACKER_URL.