Ruler refactor

[JacksonRG]

Super Zoom!

I've changed the ruler code so that you can zoom as much as you want with +/- keys. This does some math so that the number of pixels between ruler ticks is always a factor of the FPS (rounded). That way, as I start drawing the tick marks on a the first frame of a second, every following second on the timeline should be marked.

The ruler math

I did the factoring by adding to functions.js:

• I added code to find prime numbers
  • Uses sieve of eratosthenes method.
• A set to store the primes in, to avoid repeated work
• Starting at 1 frame per ruler tick, I multiply by prime factors of FPS until the tick marks are at least 40px apart.

Issues:

1. On Webkit, the timeline's shift-scroll (horizontal scroll) doesn't work.
2. On Webengine, the ctrl-scroll (zoom) doesn't work.

(These two issues are present in dev)

[JacksonRG]

Shoot! Before anyone says it, I need to get it to draw times on first load.
That bug is only a problem in browser. Its working in app.

Also, should I be worried about the build error?

[jonoomph]

@JacksonRG This PR seems to include all the other changes made in develop. It's a bit crazy looking now. @ferdnyc Is this normal, and will this merge correctly? Just double checking...

[JacksonRG]

@JacksonRG This PR seems to include all the other changes made in develop. It's a bit crazy looking now. @ferdnyc Is this normal, and will this merge correctly? Just double checking...

Sorry, Totally missed your comment. Anyway, I just rebased onto develop (I think without breaking anything).

Also since we were talking about openshot just letting users keep zooming in, I removed the scroll limmits. (at least if you scroll with - and =.

[jonoomph]

Looking much better!

[jonoomph]

@JacksonRG I just resolved the conflict on src/timeline/js/functions.js... but please double check everything still works.