all: disable log message colors outside of geth

Also tweak behaviour so colors are only enabled when stderr is a terminal.

mobile/init.go

@@ -27,7 +27,7 @@ import (
 
 func init() {
 	// Initialize the logger
-	log.Root().SetHandler(log.LvlFilterHandler(log.LvlInfo, log.StreamHandler(os.Stderr, log.TerminalFormat())))
+	log.Root().SetHandler(log.LvlFilterHandler(log.LvlInfo, log.StreamHandler(os.Stderr, log.TerminalFormat(false))))
 
 	// Initialize the goroutine count
 	runtime.GOMAXPROCS(runtime.NumCPU())