added anonymous-script.lua so item/reaction-trigger commands do not have to make a file for every trigger for simple operations

scripts/modtools/anonymous-script.lua

@@ -0,0 +1,15 @@
+--anonymous-script.lua
+--author expwnent
+--a tool for invoking simple lua scripts without putting them in a file first
+--anonymous-script "print(args[1])" arg1 arg2 # prints "arg1"
+
+local args = {...}
+
+local f,err = load('local args = {...}; ' .. args[1], '=(anonymous lua script)') --,'=(lua command)', 't')
+if err then
+ error(err)
+end
+
+--we don't care about the result even if they return something for some reason: we just want to ensure its side-effects happen and print appropriate error messages
+dfhack.safecall(f,table.unpack(args,2))
+