[modfiy/add] delete executable file and add some new execrises in c++ primer.
	deleted:    ex1_2
	deleted:    ex1_3
	deleted:    ex1_4
	deleted:    ex1_5
	new file:   ex5_12.cpp
	new file:   ex5_14.cpp
	deleted:    ex_1.8
	new file:   ex_switch.cpp
Merge branch 'master' of github.com:cheerayhuang/Garner