Roadmap to 1.0

Changes are collected in https://github.com/jlchan/StartUpDG.jl/tree/dev - [x] Fix triangle node/face ordering https://github.com/jlchan/StartUpDG.jl/pull/153 - [ ] Use https://github.com/YingboMa/SafeTestsets.jl to encapsulate tests - [x] Submit PR moving NamedArrayPartition to RecursiveArrayTools.jl - [ ] [Add tetrahedral SBP operators](https://github.com/jlchan/StartUpDG.jl/issues/13) - [x] https://github.com/jlchan/StartUpDG.jl/pull/157 - [ ] https://github.com/jlchan/StartUpDG.jl/issues/138