Implemented basic input function and tested for the three test cases

Based on http://stackoverflow.com/questions/626759/whats-the-difference-between-list-and-tuples, let's make "Links" and "Flows" a list of tuples rather than a list of lists. There is also a missing bracket at the end of the "Links" definition.

"Links" : [ (Link Rate (Mbps), Link Delay (ms), Link Buffer (KB),
                ('H' or 'R', id), ('H' or 'R', id]))]
"Flows": [ (Data Amount (MB), Flow start (s), Source host id, Destination host id) ]