Alternative Travis build

[icyrockcom]

Work in progress PR, please do not merge this yet, see below for more (too much?) details.

This is an alternative Travis build setup. Here's what I changed:

• All exercises are compiled and tested in one run
• Travis cache now has only the bower cache
• Updated many versions (both build tools and actual purescript libraries)
• Extracted common bower.json to etc/bower.json with dependencies from all exercises
• Updated the tests to remove compilation warnings due to missing / incomplete signatures
• Tests were also split into main and suites functions to help with running the tests
• Small update to Bob exercise which was failing due to recent test case updates

Sample build that demonstrates how it works:

https://travis-ci.org/icyrockcom/xpurescript/builds/278841675

The build is failing due to linter failing on:

The following UUID was found in multiple Exercism tracks. Each exercise UUID must be unique across tracks. c41a2961-f7ca-4eaf-83cf-48762fc39c06

but otherwise goes fine (finished in ~18 minutes). Fixing the linter issue would make this a good build.

Can someone let me know if this is just updating the UUIDs? Easy to do, but I was wary after finding an issue which says something to the effect of "this will delete the exercise and all its history" (exercism/discussions#159 (comment)).

I have the following additional concerns:

• Shared bower.json has to be used going forward (not sure if this is a positive or a negative)
• Each exercise now has to have exactly one module in examples/src and test folders
• This is slightly hackish, as it requires collecting and modifying the test sources (to change the module from Test.Main to Test.ExerciseName), is that acceptable from your standpoint?
• Obviously there's a possibility of interference across exercises (though previous build also shared the same bower dependencies, so had that to some degree)

If this approach is fine with you guys, I would like to polish it a bit more:

• Fix each of the exercises (it should be only copying the bower.json, but need to confirm)
• Add dependency checker to the build which would confirm that all exercises are using the same versions as the common bower.json
• Add a script to copy the common bower.json to all exercises to help with the development
• Update documentation for contributing to mention the additional restrictions

Let me know what you think, if you have additional comments / concerns. Most importantly, if I should go ahead in this direction and with the above changes.

[icyrockcom]

OK, UUID issue looks like it's due to my repository being still named xpurescript (i.e. I still have x upfront). I guess that can be ignored, since the main build passes fine.

Let me know about the other things.

[icyrockcom]

@paf31 @lpil Any comments on the above approach?

[lpil]

Hey @icyrockcom

Seems sensible to me. My only gripe is the lack of semicolons in your Javascript ;)

[icyrockcom]

Thanks @lpil! I'll work on polishing the PR then.

The semicolons, I actually prefer not having them. Most of the time, they just are syntactic noise, don't you agree? I'll add them to this PR, not a problem.

@paf31 Let me know if you have any comments from your end.

[paf31]

Sorry I don't have time to review right now, but if @lpil is happy, I say ship it.

[icyrockcom]

No worries, thanks @paf31! We can revisit later if needed.

[lpil]

I'm just teasing with the semicolons. Old habits die hard. I use prettier so I rarely type them myself.

Anyway, lets merge this :)

[icyrockcom]

@lpil "Old habits die hard." Haha, true that! :) OK, thanks for merging. I'll do the rest in another PR.