make code easier to maintain.


sql/CMakeLists.txt:
  New file
sql/Makefile.am:
  New file
sql/rpl_rli.h:
  Changed master_info into a class
sql/slave.cc:
  Moved master info functionality into rpl_mi.cc
sql/slave.h:
  Moved master info functionality into rpl_mi.cc
sql/rpl_mi.cc:
  Moved master info functionality into rpl_mi.cc
sql/rpl_mi.h:
  Moved master info functionality into rpl_mi.cc