Travisimprovements1

Suggested minor improvements to the travis config; also just testing I understand the github workflow...
As per my previous comment, I'm happy to revert style-related stuff. For what it's worth my rationale follows below, in case you're interested:

I agree with keeping things consistent, and with keeping it divided into steps; and yes you're right I wasn't being consistent. my intention was to make the grouping of each step more logical and readable, i.e. you can see at a glance which directory we're wget-ing things into from the line above, instead of having to go to the last line of the previous step. If I was to do this at all, perhaps it would have been better had I gone the whole way and done this consistently for the whole file rather than just two steps. As I say though, I'm happy to revert this bit, just let me know.