more documentation on going back and forth between object types

[ebridge2]

currently, it is unclear how to go back and forth between flash graph objects, sparse flash matrices, dense flash matrices, and R matrices. it would be good to be more clear about how this works. For example, I can convert my flashgraph to a sparse graph with fg.get.sparse.matrix(graph), but there is no way to retrieve a dense matrix from that, and consequently, I cannot use as.matrix() to convert it to a standard R matrix.