Fix #73 and #75: 401 code edge case and exceptions thrown recursively when url is invalid

[Raft08]

Hey, Here is the pull request to fix these two issue I found : #75 and #73.

Summary:

• RateLimiter removes request element from it's iterator when it fails.
• Added a case check for response code 401 in the Request class

[mattmalec]

Let's move these changes into two different PRs. I have some comments on these changes, but I'll address them in your new PRs.

[Raft08]

I will do that when I get the time, and sorry it's my first pull request that actually makes changes in the code of a project that isn't mine.

[Raft08]

First Pull Request #77, I'll wait for it to be reviewed before posting the next one