install.sh: Replace echo with printf

Based on
https://stackoverflow.com/questions/48344624/echo-prints-n-differently-between-bin-sh-and-bin-bash
recommended is to use printf, hence replaced echo.

Signed-off-by: Dhruva Gole <goledhruva@gmail.com>

Author: DhruvaG2000

install.sh

@@ -1,14 +1,19 @@
 #!/bin/bash
 
-echo "Cloning ArduinoCore API in" $HOME
-git clone git@github.com:arduino/ArduinoCore-API ~/.ArduinoCore-API
+API_FOLDER=~/.ArduinoCore-API
+if [ ! -d "$API_FOLDER" ] ; then
+	printf '%s\n' "Cloning ArduinoCore API in $API_FOLDER"
+	git clone git@github.com:arduino/ArduinoCore-API ~/.ArduinoCore-API
+else
+	printf '%s\n' "API Folder already exists, skipping clone..."
+fi
 
-echo "Commenting out WCharacter.h because it fails to build properly"
+printf '%s\n' "Commenting out WCharacter.h because it fails to build properly"
 sed '/WCharacter.h/ s/./\/\/ &/' ~/.ArduinoCore-API/api/ArduinoAPI.h > ~/.ArduinoCore-API/api/tmpArduinoAPI.h
 mv ~/.ArduinoCore-API/api/tmpArduinoAPI.h ~/.ArduinoCore-API/api/ArduinoAPI.h
 
-echo -e "\n\nLinking..."
+printf '%s\n' "Linking..."
 ln -sf ~/.ArduinoCore-API/api cores/arduino/.
 
-echo "\nModule Successfully installed..."
+printf '%s\n' "Module Successfully setup..."