Added HTTP Authentication

[msigley]

No description provided.

[bbalet]

Please don't merge this PR.
If you want to restrict the access, you can move the script in a sub folder and setup your web server accordingly (.htacces in this folder or nginx conf for this path) Moreover, the problem of this PR is that it default this behaviour for everyone.

[msigley]

I have disabled the http authentication by default to preserve the existing behavior.

I must say though that it is not a very good idea security wise to have the script publicly accessible by default. The changes I made were based on the default functionality of the wincache gui script.