Updates for Julia v1.0 (and v0.7)

Update to julia 1.0, drop julia 0.6 support (PR #17)

* Change CI to test julia 1.0 instead of julia 0.6
* Switch to newer appveyor script (from https://github.com/JuliaCI/Appveyor.jl)
* Fix `using Pkg` && switch to use default `script`.
* Fix .travis.yml Coverage `after_success` section for v0.7
* removed .travis.yml git depth && unshallow settings from
* .travis.yml: remove cd from after_success
* Bump REQUIRE to julia v0.7
* Removed Compat now that we're requiring julia 0.7!
* Removed all "VERSION" checks now that this is 1.0!