Add Unitful package for doctests.

Author: ajkeller34

.travis.yml

@@ -13,6 +13,7 @@ script:
   - if [[ -a .git/shallow ]]; then git fetch --unshallow; fi
   - julia --check-bounds=yes -e 'Pkg.clone(pwd()); Pkg.build("AxisArrays"); Pkg.test("AxisArrays"; coverage=true)'
 after_success:
+  - julia -e 'Pkg.add("Unitful")'
   - julia -e 'cd(Pkg.dir("AxisArrays")); Pkg.add("Coverage"); using Coverage; Coveralls.submit(Coveralls.process_folder())'
   - julia -e 'Pkg.add("Documenter")'
   - julia -e 'cd(Pkg.dir("AxisArrays")); include(joinpath("docs", "make.jl"))'