Better way to load and execute the load-jadeite script

[LisaAlmarode]

Loading jadeite into pharo uses a script which has to be cut and pasted into a pharo workspace. This script is MUCH better than the old way of doing the loads, but it's a bit too long for comfortable cut and paste, and there's an hacky element. It would be nice if this could be done by some kind of filein or import operation,

[ericwinger]

@LisaAlmarode I have made updates to the JfP Readme to use a startup.st smalltalk script file. Would like your feedback if that is acceptable for the alpha?

[ericwinger]

• Need to protect against rerunning startup.st if JfP project already loaded.