remove unused variables
tidy up comments
create subgraph components based on fragment name (i.e. species and reaction indeces)
create negative paths properly: the second arc of negative edges does not need to correspond to an edge in the fragment
create negative paths properly: the second arc of negative edges does not need to correspond to an edge in the fragment. resolves #5
create negative paths properly: the second arc of negative edges does not need to correspond to an edge in the fragment. resolves #5
Merge pull request #12 from waltherg/use-fragment-for-subgraph-components-debugged

Use fragment for subgraph components