Merge pull request #11 from reynoldxu/cp4

第四章修改
第二章加图修改等
Merge pull request #12 from reynoldxu/cp2

Cp2
Update 05-chapter_memory.md
merge the file system modification from reynoldxu
修改第二章API部分
chapter 2 Done
Merge pull request #14 from reynoldxu/pulls

Pulls
fix list issue
update timer.md
Update config.yml
Update template.tex
modify chapter 5 and chapter 6 API style
Modify chapter API style
Modify chapter3 API style
Update missing picture
Merge pull request #15 from reynoldxu/pulls

Pulls
Update 00-chapter3-acknowledgement.md
Modify chapter 4(IPC) API style
Merge pull request #16 from reynoldxu/pulls

Modify chapter 4(IPC) API style