naming convention for classes and functions

[fnrizzi]

• check if functions and classes have consistent naming (camelcase, or whatnot)
• make a summary of all the inconsistencies

[cwschilly]

The standard for the repo is:
Classes: PascalCase
Functions: camelCase

This has been formalized in #64

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There are some exceptions:

romtools/workflows/dakota/sampling.py

• line 161: def run_dakota_sampling()

romtools/trial_space_utils/svd_method_of_snapshots.py

• line 12: def A_transpose_dot_bImpl()
• line 72: class svdMethodOfSnapshots

romtools/trial_space_utils/outputter.py

• line 13: def npz_output()
• line 21: def hdf5_output()
• line 26: def exodus_output()

[jtencer]

We decided to switch it to use snake_case for functions to be consistent with PEP8. I updated most things to use that format, but some exceptions remain.