[*] Convert things to relative paths so the client can be hosted in a folder
[gulp] New tasks for compiling a static version (for gh-pages)
[*] Convert things to relative paths so the client can be hosted in a folder

Summary:
[gulp] New tasks for compiling a static version (for gh-pages)

[_message] Rename partial to match others, gh-pages doesn't like underscore

Test Plan: Review changes - not sure about requirejs relative paths?

Reviewers: zip

Differential Revision: https://review.inboxapp.com/D538
[readme] Mention the github pages build