Spacebar should scroll in list mode

[RubenVerborgh]

I received a report (RubenVerborgh/WebFundamentals#18) that the current spacebar behavior in Shower is non-intuitive. As you know, the space bar on webpages typically has the function of scrolling.

In slide mode, it makes sense to change this behavior, since scrolling does not apply there. This is what Shower currently does.

In list mode, however, scrolling seems to the preferred behavior. Yet Shower alters this behavior to skipping to the next slide (for which there are many other keybindings anyway). This commit fixes that behavior to scrolling in list mode.

Should you have any concerns please let me know. In particular:

• I used a case fallthrough, which the style file allows me but you might not like.
• I was not sure if I needed to update the keys.js test (is it full screen or not?), as the tests on master currently don't run.

[pepelsbey]

This is definitely not intuitive, so I’ll merge it with pleasure. I’d stil add a test for it to keys.js even though it’s failing for now so we’ll have chance not to forget about it while fixing tests.

[RubenVerborgh]

Fair enough; I just wasn't sure on how to run the keys tests by themselves. If you could explain how I can do that, I'll gladly write a test.

[pepelsbey]

@RubenVerborgh, it’s simple: grunt test and you’ll see:

FAIL 40 tests executed in 2.406s, 30 passed, 10 failed

[pepelsbey]

To run just keys.js change *.js to keys.js here:

    casperjs: {
        files: ['tests/functional/*.js']
    }

[RubenVerborgh]

Pushed tests. (2 tests of keys.js still fail, they are unrelated and failed before.)

[pepelsbey]

Released in shower-core and shower packages, thank you!