[Dillo-dev] Patch for commands.c and menu.c to enable menus

Hello, I've re-enabled the disabled menus and implemented the callback for the Help -> Dillo Manual menu item. I have also slightly tweaked the default keybindings to be more standardized. commands.c: Documentation for functions. Implemented a_Commands_manual_callback(). menu.c: Enabled Bookmarks and Help menus. Changed default keybindings to be more standard. prefs.h: Defined constant used by menu.c. Output of diff -pru for each of the files is attached. -- Chris music is what numbers feel like San Francisco, CA