Implement Cobra CLI tooling, Viper config tooling (#336)

* start pulling out + replacing urfave and config

* replace many many instances of config

* move more stuff => viper

* properly remove urfave

* move some flags to root command

* add testrig commands to root

* alias config file keys

* start adding cli parsing tests

* reorder viper init

* remove config path alias

* fmt

* change config file keys to non-nested

* we're more or less in business now

* tidy up the common func

* go fmt

* get tests passing again

* add note about the cliparsing tests

* reorganize

* update docs with changes

* structure cmd dir better

* rename + move some files around

* fix dangling comma

vendor/github.com/spf13/afero/.travis.yml

@@ -0,0 +1,26 @@
+sudo: false
+language: go
+arch:
+ - amd64
+ - ppc64e
+
+go:
+  - "1.14"
+  - "1.15"
+  - "1.16"
+  - tip
+
+os:
+  - linux
+  - osx
+
+matrix:
+  allow_failures:
+    - go: tip
+  fast_finish: true
+
+script:
+  - go build -v ./...
+  - go test -count=1 -cover -race -v ./...
+  - go vet ./...
+  - FILES=$(gofmt -s -l . zipfs sftpfs mem tarfs); if [[ -n "${FILES}" ]]; then  echo "You have go format errors; gofmt your changes"; exit 1; fi