Change to go1.6.1 and vendoring

vendor/github.com/yudai/umutex/README.md

@@ -0,0 +1,53 @@
+# Unblocking Mutex
+
+This simple package provides unblocking mutexes for those who don't want to write many `select` clauses or get confused by numerous channels.
+
+## Usage Example
+
+```go
+package main
+
+import (
+	"fmt"
+	"github.com/yudai/umutex"
+)
+
+func main() {
+	// Create mutex
+	mutex := umutex.New()
+
+	// First time, try should succeed
+	if mutex.TryLock() {
+		fmt.Println("SUCCESS")
+	} else {
+		fmt.Println("FAILURE")
+	}
+
+	// Second time, try should fail as it's locked
+	if mutex.TryLock() {
+		fmt.Println("SUCCESS")
+	} else {
+		fmt.Println("FAILURE")
+	}
+
+	// Unclock mutex
+	mutex.Unlock()
+
+	// Third time, try should succeed again
+	if mutex.TryLock() {
+		fmt.Println("SUCCESS")
+	} else {
+		fmt.Println("FAILURE")
+	}
+}
+```
+
+The output is;
+
+```sh
+SUCCESS
+FAILURE
+SUCCESS
+```
+
+`ForceLock()` method is also availale for normal blocking lock.