Start work on Container and Process model

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

execution/process.go

@@ -0,0 +1,41 @@
+package execution
+
+import (
+	"io"
+	"os"
+
+	specs "github.com/opencontainers/runtime-spec/specs-go"
+)
+
+type ProcessController interface {
+	Start(*Process) error
+	Status(*Process) (Status, error)
+	Wait(*Process) (uint32, error)
+	Signal(*Process, os.Signal) error
+}
+
+type Process struct {
+	Pid    int
+	Spec   *specs.Process
+	Stdin  io.Reader
+	Stdout io.Writer
+	Stderr io.Writer
+
+	controller ProcessController
+}
+
+func (p *Process) Status() (Status, error) {
+	return p.controller.Status(p)
+}
+
+func (p *Process) Wait() (uint32, error) {
+	return p.controller.Wait(p)
+}
+
+func (p *Process) Signal(s os.Signal) error {
+	return p.controller.Signal(p, s)
+}
+
+func (p *Process) Start() error {
+	return p.controller.Start(p)
+}