add transplant and minimum
 On branch ch13
	modified:   ch13/main.cpp
	modified:   ch13/redblacktree.hpp
add remove not tested yet
 On branch ch13
	modified:   ch13/redblacktree.hpp
fix bug
 On branch ch13
	modified:   ch13/redblacktree.hpp
testing remove
 On branch ch13
	modified:   ch13/main.cpp
fix bug in minimum method
 On branch ch13
	modified:   ch13/redblacktree.hpp
better format
 On branch ch13
	modified:   ch13/redblacktree.hpp
add sibling method
 On branch ch13
	modified:   ch13/main.cpp
	modified:   ch13/redblacktree.hpp
delete an assert condition
 On branch ch13
	modified:   ch13/redblacktree.hpp
add remove fixup, working on testing
 On branch ch13
	modified:   ch13/main.cpp
	modified:   ch13/redblacktree.hpp
fix bug: omitted x->color = black
 On branch ch13
	modified:   ch13/redblacktree.hpp
add remove fixup,tested but not 100% correct
 On branch ch13
	modified:   ch13/main.cpp
	modified:   ch13/redblacktree.hpp