[SPARK-4161]Spark shell class path is not correctly set if "spark.driver.extraClassPath" is set in defaults.conf

Author: GuoQiang Li <witgo@qq.com>

Closes #3050 from witgo/SPARK-4161 and squashes the following commits:

abb6fa4 [GuoQiang Li] move usejavacp opt to spark-shell
89e39e7 [GuoQiang Li] review commit
c2a6f04 [GuoQiang Li] Spark shell class path is not correctly set if "spark.driver.extraClassPath" is set in defaults.conf
[SPARK-4329][WebUI] HistoryPage pagenation

Current HistoryPage have links only to previous page or next page.
I suggest to add index to access history pages easily.

I implemented like following pics.

If there are many pages, current page +/- N pages, head page and last page are indexed.

![2014-11-10 16 13 25](https://cloud.githubusercontent.com/assets/4736016/4986246/9c7bbac4-6937-11e4-8695-8634d039d5b6.png)
![2014-11-10 16 03 21](https://cloud.githubusercontent.com/assets/4736016/4986210/3951bb74-6937-11e4-8b4e-9f90d266d736.png)
![2014-11-10 16 03 39](https://cloud.githubusercontent.com/assets/4736016/4986211/3b196ad8-6937-11e4-9f81-74bc0a6dad5b.png)
![2014-11-10 16 03 49](https://cloud.githubusercontent.com/assets/4736016/4986213/40686138-6937-11e4-86c0-41100f0404f6.png)
![2014-11-10 16 04 04](https://cloud.githubusercontent.com/assets/4736016/4986215/4326c9b4-6937-11e4-87ac-0f30c86ec6e3.png)

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #3194 from sarutak/history-page-indexing and squashes the following commits:

15d3d2d [Kousuke Saruta] Simplified code
c93932e [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into history-page-indexing
1c2f605 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into history-page-indexing
76b05e3 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into history-page-indexing
b2240f8 [Kousuke Saruta] Fixed style
ec7922e [Kousuke Saruta] Simplified code
755a004 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into history-page-indexing
cfa242b [Kousuke Saruta] Added index to HistoryPage