Fix spelling - Githubissues

Konbanwa Watanabe-san!

Thanks for making proxyC! You saved me a lot of implementation time by creating this package.

In this pull request, I made the following suggestions:

I fixed some small spelling errors in the documentation (f9f8469).
I removed the Collate: section from the DESCRIPTION as it is not necessary (7d24d6f).
I added travis and appveyor files (52f4849, 0aacde9). You will need to activate travis and appveyor yourself if you wish to make use of it.

I noticed that the doi listed in the DESCRIPTION does not work ─ it seems the article you are citing does not have a doi.

koheiw / proxyC