This commit prepares the frontend code to be consumed by webpack.
It is a hack: In theory, modules should be declaring and importing the
modules they depend on and the globals they expose directly.
However, that requires significant per-module work, which we don't
really want to block moving our toolchain to webpack on.
So we expose the modules by setting window.varName = varName; as
needed in the js files.
Also:
* Change fixed element positioning and fix bugs
* Move settings dropdown back to the right and add left padding to left sidebar
(imported from commit fcf903b59617687f94618a01ce7544b69f408130)
Armaan Ahluwalia
Shubham Dhama
Rafid Aslam
AZtheAsian
Allen Rabinovich
Tim Abbott