Docs: fix literal blocks and broken links

I fixed literal blocks in docs such like below:
http://docs.trafficserver.apache.org/en/latest/sdk/http-hooks-and-transactions/http-transactions.en.html
![image](https://cloud.githubusercontent.com/assets/153144/2938726/0604fdf6-d91f-11e3-973e-732ceeca8cd6.png)

and some broken links.