Compute complexity statistics

[mgalloy]

McCabe complexity statistics (McCabe cyclic, McCabe essential, McCabe modular design) were computed in the IDLdoc 2.0 code base. This functionality should be added to the IDLdoc 3.0 code base, though possibly in a simplified manner (i.e. reporting just one number).

Also, there should be user-defined limits for marking a routine as "complex" on the warnings page.

References for more information about the McCabe complexity statistics:

• McCabe pdf
• Cyclomatic complexity
• Complexity metrics

[mgalloy]

r617 adds basic cyclomatic complexity calculations. There are user-defined limits with the COMPLEXITY_CUTOFFS keyword. The complexity computation should be further refined because currently it will parse comments and string literals while also not counting CASE and SWTICH statements correctly.