Allow to set request timeout

This should fix issue #365 ; I run the tests and it seems to work as expected, please review and let me know if you see anything strange (also, I tested it against the `2.7-SNAPSHOT`, but this should probably be merged into `2.5` or `2.6` as well)

```
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] Rexster ........................................... SUCCESS [0.872s]
[INFO] Rexster: Core Components .......................... SUCCESS [19.389s]
[INFO] Rexster: RexPro Binary Protocol ................... SUCCESS [11.689s]
[INFO] Rexster: A Graph Server ........................... SUCCESS [4:53.948s]
[INFO] Rexster Kibbles: Frames ........................... SUCCESS [15.187s]
[INFO] Rexster Kibbles: General-Purpose Rexster Extensions  SUCCESS [0.140s]
[INFO] Rexster Kibbles: Sample ........................... SUCCESS [1.552s]
[INFO] Rexster Kibbles: SPARQL ........................... SUCCESS [26.058s]
[INFO] Rexster Kibbles: Batch ............................ SUCCESS [1.122s]
[INFO] Rexster Console: A Remote REPL for Rexster ........ SUCCESS [0.488s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 6:10.790s
[INFO] Finished at: Tue Nov 11 16:04:59 CET 2014
[INFO] Final Memory: 36M/151M
[INFO] ------------------------------------------------------------------------
```