Declarative application specifications for Fission (#422)

This change enables users to have declarative specifications for Fission resources. Users can specify their "app" in a set of spec files, and use a new fission CLI command to "apply" these specs to a running cluster.

The new "spec" CLI also includes archiving of local source files, and a file watcher that re-builds archives and uploads them on file changes, and a package build watcher that waits for package builds on the CLI. 

A "--spec" option is also added to "function create", and will be added to other resources in future changes.  This option causes a YAML to be outputted to the specs directory instead of the resource being created on the cluster.

The CLI "fission spec --help" outputs usage information.

examples/go/README.md

@@ -1,40 +1,17 @@
-# Go examples
+# Hello World in Go on Fission
 
-The `go` runtime uses the [`plugin` package](https://golang.org/pkg/plugin/) to dynamically load an HTTP handler.
-
-## Requirements
-
-First, set up your fission deployment with the go environment.
-
-```
-fission env create --name go-env --image fission/go-env:1.8.1
-```
-
-To ensure that you build functions using the same version as the
-runtime, fission provides a docker image and helper script for
-building functions.
-
-## Example Usage
-
-### hello.go
-
-`hello.go` is an very basic HTTP handler returning `"Hello, World!"`.
+`hello.go` is an very simple fission function that says "Hello, World!".
 
 ```bash
-# Download the build helper script
-$ curl https://raw.githubusercontent.com/fission/fission/master/environments/go/builder/go-function-build > go-function-build
-$ chmod +x go-function-build
+# This command creates the environment and function, and waits for the
+# function build.  Look at the YAML files in specs/ for details about
+# how those are specified.
+$ fission spec apply --wait
+1 environment created
+1 package created
+1 function created
 
-# Build the function as a plugin. Outputs result to 'function.so'
-$ go-function-build hello.go
-
-# Upload the function to fission
-$ fission function create --name hello --env go-env --package function.so
-
-# Map /hello to the hello function
-$ fission route create --method GET --url /hello --function hello
-
-# Run the function
-$ curl http://$FISSION_ROUTER/hello
+# This run the function and prints its output
+$ fission function test --name hello
 Hello, World!
 ```