Simulation parameters to be changed from Python

[vcellmike]

1. The number of runs
2. Number of molecules of each type
3. Kinetic parameters for each reaction ('pY_SH2 binding_1' , ..., ...)

When displaying the content of the input file, print each reaction on two lines:

'pY_SH2 binding_1': site .. of .. binds ... on rate: ..., off rate: ...