Added in cut, copy and paste to the context menu. Also removed find pattern, as that's no longer a valid command. Also made it so commands only show up if their predicates are valid.

data/core/command.lua

@@ -41,6 +41,9 @@ function command.get_all_valid()
   return res
 end
 
+function command.is_valid(name, ...)
+  return command.map[name] and command.map[name].predicate(...)
+end
 
 local function perform(name, ...)
   local cmd = command.map[name]