Fix security issue: set 'register_masterkey' field as autocomplete=off.
If a user has restored his wallet from his masterkey, such secret key
is persisted in clear-text into the browser.
Upgrade build system.

- Builds now automatically include a version number based on git.
- Ability to create "bundles" - trees assembled based on source files.
- Single index.html template that is processed into different versions.
Remove unused code "calculate_send".
New utility script to extract translatable strings.
Federation client support. (In progress.)
Added first example translatable string.
Fix indentation.
Remove analytics.js. (Use config.js instead.)
Add watch tasks for index and config.
Some tweaks for example config.
Added Convert tab. Fixes #916. Has some bugs
Merge pull request #993 from alexdupre/autocomplete

Fix security issue: set 'register_masterkey' field as autocomplete=off.
Contacts tab: Error message fixes #967
Update upstream. Websocket support. Fixes #965
Fix status bar position for small screens
Add rpNotXrp validator. Used for currency select boxes
Trust tab: Don't allow xrp trusts. Fixes #560
Ripple URI: Direct link to wallet. Fixes #182
Trust tab: Required fields
Trade: Should have some of the funds to be offered. Fixes #198, fixes #259