Implement progression beyond Grade A

[abesto]

(Resolves #47) Preview build is available at https://d4sk2ytizwr62.cloudfront.net so you can click around to get a proper feel. (Watch out, trying to load a sub-page directly, like https://d4sk2ytizwr62.cloudfront.net/career, will not work. That's expected, it's a limitation of the tech I used to quickly throw up this preview)

Progression before Grade A

No changes

Reaching Grade A

Race result dialog is unchanged:

However, after this, we show XP progression towards "Mastery" (open to different wording). The icon for the grade has a solid background, but no checkmark, just like other grades while they're in progress.

Progress towards mastery

Race results are reported the same way as before:

Achieving Mastery

Instead of the "You've advanced to Grade X" message, there's a new one; very open to a better message here

I've also added an achievement for each discipline, with progress tracking XP from 0 to Mastery. Open to better names for the achievements.

Racing after Mastery

We keep generating races even in mastered disciplines, but:

• No XP progress bar
• Grade A has a checkmark on the grade stepper

Also no XP progress bar in the race result dialog

[rsr427]

This looks great. Until we can implement some sort of "Championship Series", this seems like an appropriate reward. Do we show total XP in numerical terms? Maybe we use that as a global rank in case people actually make it to multiple careers. (I'm only 10 races into my career...)

[abesto]

Do we show total XP in numerical terms?

Not at the moment, but that's fairly easy to add. On the other hand: I feel like we get the same value from the achievements?

This looks great. Until we can implement some sort of "Championship Series", this seems like an appropriate reward.

Alright, here we go then; this will go live very soon. Watch out for a changelog popup as well ;)