shanil create lattice route and output correct oxDNA format

[shanilpanara]

Update

@debeshmandal We can now generate a very simple route for a given square polygon.

Issues

As in #35 we need to define our lattice so that we are creating the correct distance for lattice spacings in between lattice sites.

• Lattice units -> 1 unit = 1 basepair distance
• Need to convert this into the correct form before creating LatticeNodes

The route generated by the lattice is:

When visualised in ovito:

Closes #34

[debeshmandal]

Closing because this has been merged into #42