Adding immutable requests.
Create a new request object on each change.
Adding a test to make sure we use a new mutable RequestBuilder each time.
Grammar fix in promise docs. Fixes issue #48
Merge pull request #49 from adamdecaf/promise-doc-fix

Grammar fix in promise docs. Fixes issue #48
Merge branch 'master' into immutable-requests-squashed
Adding docs.
Merge branch 'sippy' of github.com:dispatch/reboot into sippy
Merge pull request #51 from adamdecaf/immutable-requests-squashed

Immutable requests