Case insensitivity implemented - by storing key in lower case

[PandaWood]

I stored the key as lower case, to avoid adding a load of toLowerCase statements - though I still needed a few.
I tried using a case-insensitive regex but it fails one important test that deals with encoding, so toLowerCase it is
I've also removed forEach - it's time to let go - I'll understand if you don't want this. But I'll keep it on my fork

These commits need to be squashed, only the last implements the idea of storing the key lower case

[derek-watson]

@PandaWood sorry it has taken so long to address this - are you still interested in discussing? There are some aspects of the spec that assuming case insensitivity violates, and so I'm wondering if we can do a constructor switch or something.

[PandaWood]

Hi @derek-watson ,
Right, I suppose a constructor arg might be the only way then, although probably be a little awkward
eg something like new Uri({nocase: true}, url).getQueryParam('bob')