added atomEnergies for M08SO/MG3S* to statemech

this will be useful in the future when others want to use this method
for thermo calculations.
Correct gaussian environment variable when path is a list

This should not affect the environment variable that provides
a singe path to the g09 executable.

Some systems provide the environment variable as a list of
paths. To correct this, the environment variable
`GAUSS_EXEDIR`, which contains all these paths, is split
at the `:`. Each path is then searched for the g09 executable.
Update RMG example 1,3-hexadiene with multiplicity label
Update RMG example c3h4 with multiplicity label
Update RMG example ch3no2 with multiplicity label
Update RMG example diesel with multiplicity label
Update RMG example e85 with multiplicity label
Update RMG example liquid_phase with multiplicity label
Update RMG example methylformate with multiplicity label
Update RMG example minimal with multiplicity label
Update RMG example minimal_sensitivity with multiplicity label
Update RMG example TEOS with multiplicity label
Add multiplicity label to loadEntry for transport libraries
Add multiplicity label to loadEntry for thermo libraries and groups
Add multiplicity label to loadEntry for statmech depository
Add multiplicity label to class Entry and loadEntry for forbidden
structures
Add multiplicity label to loadEntry for kinetics depository
Add multiplicity label to loadEntry for kinetic groups
Add multiplicity label in loadEntry for kinetic libraries
Add multiplicity label to group.py

- remove multiplicity from GroupAtom
- add multiplicity to Group
- update __gainRadical() and __loseRadical()
- update equivalent() and isSpecificCaseOf()