Rename repository

[BeastyBlacksmith]

As discussed in #12 the target audience for this course are people with some experience in programming, that want to pick up julia.

Therefore the name of the repository should be changed at some point. My current favorite name would be julia-expert-trebuchet or julia-intermediate-trebuchet depending on naming conventions in the carpentries.

[tkphd]

My impression from working through the lesson is that the level of programming experience required is rather low, and the concepts covered (help menus, operators, conditionals, loops, and importing packages) are under the novice umbrella. Separating the code into a separate file is novice-plus, and the final discussion of packaging the code is probably intermediate, but the lesson overall feels comfortably entry-level.