Initialize list of bonds lazily. The bond list in an Atom is now
initialized with Collections.emptyList(), rather than an ArrayList. This
doubles the speed of allocating Atoms, since the bond list is not
created.
Merge pull request #79 from pwrose/master

Initialize list of bonds lazily. The bond list in an Atom is now
Merge pull request #8 from biojava/master

Catch back up with biojava/master