add HTTP(S)_PROXY and http(s)_proxy to environment variables

According to issue #43: curl, wget, perl library and python library read environment variables to configure http and https proxy. But the current curl uses upper case letters and the current wget uses lower case letters. (Found in the man pages.) The perl library could have changed the writing in the history. (Found different information on web pages.)

To support all tools in all versions HTTP(S)_PROXY and http(s)_proxy exports are added in the orc_loadURL function.

o.rc

@@ -27,10 +27,35 @@ orc_loadURL () {
   # Loads from an URL via curl, wget or perl.
   # Argument: The URL to download, https is supported.
   # Output to stdout: The content of the URL document.
+  # Global: http(s)_proxy variables will be used.
   if [ $# -ne 1 ]; then
     echo 'Error: argument must be one URL to load'
     return 1
   fi
+  # A proxy could be set via environment variables to the tools.
+  # But some tools in some versions needs lower case and some
+  # needs upper case variable names. To increase portability
+  # both cases will be exported.
+  export http_proxy
+  export HTTP_PROXY
+  if [ -n "$http_proxy" ]; then
+    if [ -n "$HTTP_PROXY" ] && [ "$HTTP_PROXY" != "$http_proxy" ]; then
+      echo 'Warning, ignore HTTP_PROXY value and use http_proxy value.'
+    fi
+    HTTP_PROXY=$http_proxy
+  elif [ -n "$HTTP_PROXY" ]; then
+    http_proxy=$HTTP_PROXY
+  fi
+  export https_proxy
+  export HTTPS_PROXY
+  if [ -n "$https_proxy" ]; then
+    if [ -n "$HTTPS_PROXY" ] && [ "$HTTPS_PROXY" != "$https_proxy" ]; then
+      echo 'Warning, ignore HTTPS_PROXY value and use https_proxy value.'
+    fi
+    HTTPS_PROXY=$https_proxy
+  elif [ -n "$HTTPS_PROXY" ]; then
+    https_proxy=$HTTPS_PROXY
+  fi
   if orc_existsProg curl; then
     curl --silent --location --insecure -- "$1"
   elif orc_existsProg wget; then