Rubocop name cops

[hainesr]

This PR goes through and cleans up rubocop naming cops that don't affect the API.

There were many variables/parameters/etc named in camelCase style, possibly a hangover from the early days of this library and its Java-like roots. This PR renames them to ruby standard snake_case style.

Most names have been translated as simply as possible - e.g. entryName to entry_name - but some have been simplified as well - e.g. aProc to proc. There are no changes to functionality in this PR; any other changes, such as formatting, have only been done to conform to our existing rubocop standards.

[coveralls]

Coverage remained the same at 95.767% when pulling ce17c57 on hainesr:rubocop-names into 8d91d00 on rubyzip:master.

[jdleesmiller]

Thanks for taking this on!

I have now read through. It may look like a lot of comments, but they are for a small number of repeated things.

[hainesr]

I've done the proc -> a_proc changes. You were definitely right about it being potentially dangerous, and I'm surprised that Rubocop doesn't have an opinion on it, like it does for open...

[jdleesmiller]

OK, thanks. All looks good.

On the changes to strings / file names: in general, changing both tests and code at the same time makes me a bit nervous, so I'd lean toward making the minimal set of changes possible to the tests. However, I don't see any particular problems here; it seems unlikely that the case of the the files in the tests is a significant factor in the test suite coverage.

[hainesr]

Thanks. Point taken about changing code and tests together; I agree. But as you say these changes are fairly safe in this instance...