From: Kir Kolyshkin <kolyshkin@gmail.com>
Subject: arduino-builder: make -tools optional

This fixes the error from arduino-builder that it is called (by the arduino
GUI 1.6.6 as packaged in Fedora) without the (mandatory) option -tools.

In fact, if all paths to tools are well known, this option is not required.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

diff -ur arduino-builder-1.0.5/main.go arduino-builder-1.0.5-my/main.go
--- arduino-builder-1.0.5/main.go	2015-11-02 01:21:00.000000000 -0800
+++ arduino-builder-1.0.5-my/main.go	2017-04-06 19:15:21.051369255 -0700
@@ -191,7 +192,7 @@
 		return
 	}
 
-	err, printStackTrace = setContextSliceKeyOrLoadItFromOptions(context, toolsFoldersFlag, buildOptions, constants.CTX_TOOLS_FOLDERS, FLAG_TOOLS, true)
+	err, printStackTrace = setContextSliceKeyOrLoadItFromOptions(context, toolsFoldersFlag, buildOptions, constants.CTX_TOOLS_FOLDERS, FLAG_TOOLS, false)
 	if err != nil {
 		printError(err, printStackTrace)
 		defer os.Exit(1)