Add attribute saveEdgeSpecies to input.py

If saveEdgeSpecies == True RMG will save seperate chemkin and HTML files
for the edge of the model. This was very useful for debugging and has
been requested y the other develoeprs to become official.
Modifiy output.py to be able to distinguish between core and edge

The additional string attribute in saveOutputHTML (either 'core' or
'edge') decides which part of the model is written into HTML. This was
very useful for debugging and has been requested y the other developers
to become official.
Make saveChemkingFile() able to handle core and edge of the model

This was very useful for debugging and has been requested by the other
developers
to become official.
Modify main.py to save output depending on saveEdgeSpecies attribute

This was very useful for debugging and has been requested by the other
developers
to become official.
Remove saveSpeciesDictionaryEdge()

Its functionality in now included in saveSpeciesDictionary()
In debugging mode, print pdep network's high P limit reactions to chemkin file.

That way you don't have to dig through the pdep network's py file when
in debug mode.