Create topicswap

Added helpfile
ref: thomasdubell/atheme@0e0671e
ref: thomasdubell/atheme@7bfff15
gameserv: mark strings for i18n

ref: shalture/shalture@a2ceeea
Add STR_NOT_AUTHORIZED define for a common string

"You are not authorized to perform this operation." and variations of it
were littered all over the code. Having a #define for it will help
maintain consistency.