Refactor ES6 module structure/split up Util

This commit restructures many of the ES6 modules, splitting them
up to actual export multiple functions instead of a single object.

It also splits up Util into multiple sub-modules, to make it easier
to maintain.

Finally, localisation is renamed to localization.

.gitignore

@@ -7,3 +7,5 @@ utils/websockify
 /build
 /lib
 recordings
+*.swp
+*~