Add support for python3

bin/gng

@@ -140,6 +140,20 @@ bootstrap_help() {
   printf '\t%s\n' "-h, --help: Prints help"
 }
 
+function parse_gradle_version() {
+    if command -v python &> /dev/null
+    then
+        python -c "import json,sys; obj=json.load(sys.stdin); print obj['version'];"
+        return
+    fi
+    if command -v python3 &> /dev/null
+    then
+        python3 -c "import json,sys; obj=json.load(sys.stdin); print (obj['version']);"
+        return
+    fi
+    die "Cannot find python/python3 interpreter !"
+}
+
 function bootstrap() {
   local _arg_version _arg_distribution_type _arg_destination_dir
   _arg_version="latest"
@@ -182,7 +196,7 @@ function bootstrap() {
   if [[ "${_arg_version}" == "latest" ]]; then
     info "Fetching the latest Gradle version from services.gradle.org"
     _arg_version=$(curl -m 60 -sSL "https://services.gradle.org/versions/current" |
-      python -c "import json,sys;obj=json.load(sys.stdin);print obj['version'];") || die "Failed to fetch the version info!"
+                       parse_gradle_version) || die "Failed to fetch the version info!"
     info "The latest Gradle version is ${_arg_version}"
   fi
   __install_gw "${_arg_version}" "${_arg_distribution_type}" "${_arg_mirror:-}" "${_arg_destination_dir}"