Fix Dedication Loss on Logout

Added a fix to dedication loss on log out. Used subpower on rings and
added an addMod for MOD_DEDICATION_CAP to the effect\dedication lua
file.

If you see anything off about this just let me know in the comments and I'll fix it right up. Tested on my test server and didn't have any issues. 
bonus += dsp_cap((exp * percentage) / 100, 0, cap)

reason: you don't get the full multiplier if its more than the remaining cap amount
other than that, it's good, but i'd like to also delete MOD_DEDICATION and MOD_DEDICATION_CAP from modifier.h and status.lua and make sure it still compiles