Remove CasperJS from the GeoExt repository only installing it via NPM if needed.

[bentrm]

These changes aimed to remove unrelated files from the GeoExt repository by removing the duplicated CasperJS repository. Readme.md, .travis.yml and .gitignore have been updated accordingly to make sure everything still works as expected.

I hope I'm not intruding on other build mechanics that are not apparent via the repo. If these changes are a no-go, I'm ok with it.

[marcjansen]

I like this. I always wanted to remove the copied casperjs, but I am glad you finally did it.

This change does introduce npm as new dependency, but I think this is absolutely OK.

I'd love to hear a short sentence from @chrismayer whether everything works for him on his windows machine, but otherwise this looks great to me.

Thanks anyhow, I am sure that we'll merge this sooner or later.

Hey @bentrm, you may be interested to also have a look at #286 while you're looking at headless testing.

[bentrm]

Good point, I kind of disregarded Windows. Though, I'm not sure if the headless tests have been working on Windows anyway. I just tried it with a fresh clone on a development machine. Seems like you have to run batchbin\casperjs instead of bin\casperjs. Still, no luck with a fresh branch nor this PRs branch.

[marcjansen]

I am pretty sure they didn't really work on windows. Let's see if @chrismayer finds out something. npm should help at least with the installation, right?

I personally don't think this should block this, as the headless tests are an added value for CI mainly.

And I really want to remove all the doubled content (14k lines).

[chrismayer]

No, it did not work on Windows before. So we do not break anything with this PR and I am +1 for merging this.
I had also some problems running the headless tests after merging this PR. Maybe we open up another issue but with minor priority.

Thanks for tackling this!

[marcjansen]

Thanks @chrismayer & @bentrm.

[marcjansen]

11 additions and 14,766 deletions

Awesome 😏 👍