Pomf's old JavaScript is a frozen dependency hell with an old version of
Zepto. The amount of code included has reached the point of
unmaintainability, where nobody really understands very well how the
code works.

This code gets rid of all the previous client-side JavaScript and
replaces it with new, vanilla JavaScript. No dependencies required. This
new JavaScript should be quite a bit faster too.

Browser backwards compatibility has not been tested yet, however it is
expected that IE10 and later will work, improving our current backwards
compatibility.

Reviewed-by: Eliot Whalan <ewhal@pantsu.cat>
[wub@partyvan.eu: Added Git commit message and fixed Git branching.
Reverted /*   outline-offset: -2px;*/ removal.]
Signed-off-by: Juuso Lapinlampi <wub@partyvan.eu>

Lint our spaghetti JavaScript code to be at least slightly more
readable. Configuration used is ESLint 1.7.x and airbnb/legacy.

It's been so long I cannot remember every change that was done, but long
story short: all the ESLint errors are now gone, at least at the date of
last commit.

moep contributed some ideas for patches: some were implemented, some
were discarded as the time and patience for merging this ran out. Thus,
there are still ESLint warnings about anonymous functions.

I don't feel like spending much more time on this. The future Pomf 2.1
development branch will replace the JavaScript code in its entirety,
courtesy of luminarys@.

Suggested-by: moep
Tested-by: Eliot Whalan <ewhal@pantsu.cat>

OK ewhal@, maybe a vague OK from luminarys@ a long time ago

Very short identifier names usually make the code harder to read and
potentially less maintainable.

Fixes two ESLint id-length errors using airbnb/legacy config.

Suggested-by: avail <avail@pomf.se>

JSHint is "deprecated" in favor of ESLint. Personally I have not used
JSHint ever since switching to ESLint.

Vague OK from ewhal@

Fixes ESLint id-length errors using airbnb/legacy config. Variable "i"
is ignored as an exception.

I've also avoided creating new errors with these changes, so this also
fixes some no-unused-vars and avoids creating vars-on-top errors.

Prefix jQuery object variables with a $

Airbnb style guide recommends checking booleans this way or using
(!!window.FormData). The latter is more confusing for many.

While !! is indeed 0.2% faster than Boolean(), it's called
micro-optimization. There is no noticeable difference to the user in our
use scenario and I prefer more readable code any day.

Fixes ESLint no-undefined warning using Airbnb ES5 config.

Reference: https://jsperf.com/boolean-conversion-speed

Fixes ESLint no-param-reassing warning.

This fixes Airbnb ES5 style guide violations.