Switch to using SIMD-oriented Fast Mersenne Twister for random number generation.

In testing, reduced random number generation time by a factor of 8-10.
Drops support for processors older than Pentium 4.
Drop Mersenne Twister library; use a C++ SFMT library.

--HG--
branch : trunk

src/server/worldserver/CMakeLists.txt

@@ -46,7 +46,7 @@ include_directories(
   ${CMAKE_BINARY_DIR}
   ${CMAKE_SOURCE_DIR}/dep/gsoap
   ${CMAKE_SOURCE_DIR}/dep/sockets/include
-  ${CMAKE_SOURCE_DIR}/dep/mersennetwister
+  ${CMAKE_SOURCE_DIR}/dep/sfmt
   ${CMAKE_SOURCE_DIR}/src/server/collision
   ${CMAKE_SOURCE_DIR}/src/server/collision/Management
   ${CMAKE_SOURCE_DIR}/src/server/shared