Changing behavior of kineticsFamilies field loading of families.

Now the following options for kineticsFamilies in the input file are allowed:

- When kineticsFamilies field is set to 'default', the RMG recommended families
  are loaded from the database.  This is also selected when the kineticsFamilies
  field is completely missing

- 'all' indicates all families are turned on.

- 'none' means none of the families are turned on.  This is good for debugging.

- A list of families means only those are selected, e.g. ['H_Abstraction','R_Recombination'].
  You can also deselect all but certain families by using the ! flag,
  e.g. ['!Intra_Disproportionation','Substitution_O']

Added additional error raising in rmgpy.data.kinetics in case any of the if/elif
statements fall through when code changes occur.
Set minimal example to 'default' kineticsFamilies.