Add the build script for zephyr-sketch-tool

Since I had it and others may run into needing to build it again.
...
Also added to gitignore the distrib

Author: KurtE

.gitignore

@@ -7,3 +7,5 @@ cflags.txt
 cxxflags.txt
 includes.txt
 provides.ld
+cores/arduino/api
+/extra/zephyr-sketch-tool/distrib

extra/zephyr-sketch-tool/build.sh

@@ -0,0 +1,20 @@
+VERSION=$1
+
+mkdir -p distrib/linux_amd64
+GOOS=linux GOARCH=amd64 go build && mv zephyr-sketch-tool distrib/linux_amd64/zephyr-sketch-tool
+
+mkdir -p distrib/linux_arm64
+GOOS=linux GOARCH=arm64 go build && mv zephyr-sketch-tool distrib/linux_arm64/zephyr-sketch-tool
+
+mkdir -p distrib/macos_amd64
+GOOS=darwin GOARCH=amd64 go build && mv zephyr-sketch-tool distrib/macos_amd64/zephyr-sketch-tool
+
+mkdir -p distrib/windows_386
+GOOS=windows GOARCH=386 go build && mv zephyr-sketch-tool* distrib/windows_386/zephyr-sketch-tool.exe
+
+cd distrib
+
+tar -czf zephyr-sketch-tool-${VERSION}-linux_amd64.tar.gz linux_amd64
+tar -czf zephyr-sketch-tool-${VERSION}-linux_arm64.tar.gz linux_arm64
+tar -czf zephyr-sketch-tool-${VERSION}-macos_amd64.tar.gz macos_amd64
+zip -r zephyr-sketch-tool-${VERSION}-windows_386.zip windows_386