Update deps without licenses

The following packes did not have discernible LICENSE files at the hash we have
vendored:
  github.com/beorn7/perks
  github.com/daviddengcn/go-colortext
  github.com/garyburd/redigo
  github.com/prometheus/common
  github.com/shurcooL/sanitized_anchor_name
  github.com/stretchr/objx

This commit updates all of them and updates the central LICENSE file.

vendor/github.com/prometheus/common/model/metric.go

@@ -15,11 +15,15 @@ package model
 
 import (
 	"fmt"
+	"regexp"
 	"sort"
 	"strings"
 )
 
-var separator = []byte{0}
+var (
+	separator    = []byte{0}
+	MetricNameRE = regexp.MustCompile(`^[a-zA-Z_][a-zA-Z0-9_:]*$`)
+)
 
 // A Metric is similar to a LabelSet, but the key difference is that a Metric is
 // a singleton and refers to one and only one stream of samples.
@@ -79,3 +83,16 @@ func (m Metric) Fingerprint() Fingerprint {
 func (m Metric) FastFingerprint() Fingerprint {
 	return LabelSet(m).FastFingerprint()
 }
+
+// IsValidMetricName returns true iff name matches the pattern of MetricNameRE.
+func IsValidMetricName(n LabelValue) bool {
+	if len(n) == 0 {
+		return false
+	}
+	for i, b := range n {
+		if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || b == ':' || (b >= '0' && b <= '9' && i > 0)) {
+			return false
+		}
+	}
+	return true
+}