Fix p2asmaven causes NPE

[nedtwigg]

Failed attempt to fix #144.

[nedtwigg]

This is a janky fix, but it does bring p2asmaven back to its previous behavior.

• basically our old 4.7.2 bootstrap requires Java 8
• but our new 4.13.0 bootstrap doesn't work with p2asmaven, and I cannot figure out why
• so, for just the case of p2asmaven, we use the old 4.7.2 bootstrap, which involves bringing back parts of the old EquinoxLauncher

This is super-hacky, but it means nobody needs to be stuck on an old version anymore.