Update select.c
Update legacy.c

修改12-15,23-48，66，78,90-92
Update mem5.c

完善源码分析
Update sqliteInt.h
Update sqliteInt.h
Update malloc.c
Merge pull request #107 from qihuidan/master

Update select.c
Merge pull request #124 from yujiesun/patch-4

Update sqliteInt.h
Merge pull request #113 from 520060628/master

Update legacy.c
Merge pull request #121 from momoye/patch-4

Update mem5.c
Merge pull request #139 from Riverhe2014/master

Update malloc.c
Merge pull request #123 from xiaovyoyo/master

Update sqliteInt.h
Merge pull request #32 from HuiLi/master

合并更新