dev: roxygenise before rstudio build
suggest nat.flybrains for tests
Add tests from nat.flybrains

* design is that we will use data from nat.flybrains for testing
* but nat.flybrains is an optional suggestion and the tests are guarded
Merge branch 'feature/movetests'

* feature/movetests:
  Add tests from nat.flybrains
  suggest nat.flybrains for tests
Add package docs
Make extrabridge/mirror nat.templatebrains options
Give xform_brain a via option

* closes jefferislan/nat.flybrains#8
* includes a test
Bump version to 0.2