Assemble sequences with multiple locations

[bbartley]

We can represent an insertion into a genome by giving two Location objects to describe where the old genome goes in the new genome. i.e., if we are putting in 2 kilobases starting at location 1001 in a length 10,000 genome, the Location assigned by a SequenceAnnotation to the Component would be Location is 1-1000 and Location is 3001-12000.

Right now, however, pySBOL will not stitch together the pieces correctly, when asked to assemble this sequence.

[tcmitchell]

See SynBioDex/libSBOL#216

[bbartley]

Postponed from 2.3.3 milestone until later.