built-in WM_APPCOMMAND support

scripts/powershell/show-in-file-explorer.ps1

@@ -0,0 +1,14 @@
+
+# Shows the current file in File Explorer
+
+# In input.conf add: <key> script-message show-in-file-explorer
+
+$code = {
+    if ($args[0] -eq 'show-in-file-explorer')
+    {
+        # probably works only with shell execute for which powershell has no built-in support
+        [Diagnostics.Process]::Start('explorer.exe', '/n, /select, "' + $mp.get_property_string('path') + '"')
+    }
+}
+
+$mp.register_event("client-message", $code)