Calculation type identification during parsing

[ezpzbz]

Currently, I only look for Opt as an example to parse the optimization job data. However, these keywords are not case sensitive in Orca and user may provide for example opt.
There are two solutions:

• Using regular expressions to identify correct ones.
• Converting input keyword strings to lower case while generating the input.
  So far, I think we need both implementations as there are keywords like COPT too for geometry optimization and not seeing it now may result in future issues.

[ezpzbz]

Solved in #6