resources: Parse YAML infinity specifications correctly

This makes it easier to specify an infinite rate.

examples/file5.yaml

@@ -0,0 +1,13 @@
+---
+graph: mygraph
+resources:
+  file:
+  - name: file1
+    meta:
+      limit: .inf
+      burst: 0
+    path: "/tmp/mgmt/hello"
+    content: |
+      i am a file
+    state: exists
+edges: []

resources/resources.go

@@ -24,6 +24,7 @@ import (
 	"encoding/gob"
 	"fmt"
 	"log"
+	"math"
 	"os"
 	"path"
 	"sync"
@@ -272,7 +273,8 @@ func (obj *BaseUID) Reversed() bool {
 
 // Validate reports any problems with the struct definition.
 func (obj *BaseRes) Validate() error {
-	if obj.Meta().Burst == 0 && !(obj.Meta().Limit == rate.Inf) { // blocked
+	isInf := obj.Meta().Limit == rate.Inf || math.IsInf(float64(obj.Meta().Limit), 1)
+	if obj.Meta().Burst == 0 && !isInf { // blocked
 		return fmt.Errorf("Permanently limited (rate != Inf, burst: 0)")
 	}
 	return nil
@@ -291,6 +293,9 @@ func (obj *BaseRes) Init() error {
 	if obj.Meta().Burst == 0 && obj.Meta().Limit == 0 { // blocked
 		obj.Meta().Limit = rate.Inf
 	}
+	if math.IsInf(float64(obj.Meta().Limit), 1) { // yaml `.inf` -> rate.Inf
+		obj.Meta().Limit = rate.Inf
+	}
 
 	//dir, err := obj.VarDir("")
 	//if err != nil {