Tidy up all .pm and .t

[yoshikazusawa]

8dc5646 I applied perltidy to all .pm and .t files in accordance with "Code style and tidying" in CONTRIBUTING.md.
b6d8da0 Also made some manual adjustments to tab characters in comments.

3bcaa63 Additionally, fix small path correction in CONTRIBUTING.md.

[oalders]

Thanks for this, @yoshikazusawa! I would love to tidy the entire distribution, but I think this would make it harder to merge (or even review) the existing pull requests. There is a note about that in the README section that you linked to:

as this is an old distribution and styling has changed somewhat over the years, please keep your tidying constrained to the portion of code or function in which you're patching.

I think there would be no issue in merging the first two commits in this pull request, though.

Ideally we would have dealt with all of the open pull requests some time ago, but it's not always that easy. 😞

[yoshikazusawa]

@oalders Thank you for your response and for explaining the notice. I apologize for overlooking that.
I will try to make the adjustments so as not to affect with other PRs.

[oalders]

I think if you drop 8dc5646 then we can go ahead and merge this. Or I can cherry-pick the commits at the command line. Whatever works for you.

[yoshikazusawa]

@oalders Thank you for your advice. I have tried again in #204, so I would appreciate it if you could take a look.