Minor updates to the documentation

Firstly, I have documented the use of constants in the client API stats function. Instead of using the value 20, it uses INTERVAL_30_DAYS as added in e2b638dfa3734f6c2b9e10f18e11e83269bc836d by gregschoen.

Secondly, I have updated the URL for CloudFlare to use https. This is because CloudFlare prefers it users to use https to access their site.

Thanks guys for making this.