AMUSE stuff

[teuben]

A small avalanche of AMUSE inspired changes, inspired by MODEST25-SPZ

• bhtree revived
• amuse.1 man page
• amuse_convert.py conversion between (some) formats
• amuse1.py - example integrator without bells and whistles]
• hop for NEMO installed, since we still need a clumpfinder (rockstar is another option)

Perhaps nice to add a few parallel examples,e.g.

• integrator with choice of integrator, like rebound's reb_integrate
• orbits in potentials
• figure 8 orbit
• map of a potential

[teuben]

At neat one will be the new amuse_for_nemo notebook, which is a hybrid %%bash + python notebook.

[teuben]

amuse_integrate.py is the updated version of amuse1.py