Remove bin/ directory in favour of an add_path.sh script that can be sourced

Remaining file in bin/ will be moved out as part of !34

add_path.sh

@@ -0,0 +1,17 @@
+# This shell snippet appends useful esp-idf tools to your PATH environment
+# variable. This means you can run esp-idf tools without needing to give the
+# full path.
+#
+# Use this script like this:
+#
+# source ${IDF_PATH}/add_path.sh
+#
+if [ -z ${IDF_PATH} ]; then
+	echo "IDF_PATH must be set before including this script."
+else
+	IDF_ADD_PATHS_EXTRAS="${IDF_PATH}/components/esptool_py/:${IDF_PATH}/components/partition_table/"
+	export PATH="${PATH}:${IDF_ADD_PATHS_EXTRAS}"
+	echo "Added to PATH: ${IDF_ADD_PATHS_EXTRAS}"
+fi
+
+