Remove usage of .shepherd-transparent-text class

[BrianSipple]

The shepherd-transparent-text CSS class is used pretty liberally throughout the test dummy app, and it's even used as a default class for the "error" step we add in the tour service.

However, I don't think this class is actually a part of the styles for shepherd, and we don't have any style rules for it here. It seems to be limited to shepherd's test dummy app styling.

If that's the case, I think we should get rid of it here to eliminate some confusion.

[BrianSipple]

I think this also applies to the .shepherd class -- in both ember-shepherd and shepherd.

[RobbieTheWagner]

@BrianSipple are you saying just remove unused classes from demos? The demos use some custom classes, to show that you can pass classes in and such.

[BrianSipple]

I'm not opposed to having dummy class names when we're demoing such usage. That said...

• I might make it a bit more clear that that's what they are. (Something like my-custom-class-name).
• I still think there are several clean-up opportunities -- especially the case where these classes made it in to the addon code.

[RobbieTheWagner]

Totally agree with that. Those classes are all arbitrary. Having a class of shepherd-open doesn't guarantee the step is open either. We can probably remove all those classes except shepherd-theme-arrows.