Expandable arguments for web UI

Adds possibility to expand arguments on web UI to see full value on click.

Few screenshots to illustrate how it looks:

1. current master:

  ![2013-12-28 23 50 58](https://f.cloud.github.com/assets/789247/1818449/18aaf146-7005-11e3-8145-0e4afd78aef2.png)

2. with expandable arguments - collapsed (by default):

  ![2013-12-29 00 08 19](https://f.cloud.github.com/assets/789247/1818452/3a158f4e-7005-11e3-8ce8-227953710714.png)

3. with expandable arguments - expanded (after click):

  ![2013-12-29 00 08 37](https://f.cloud.github.com/assets/789247/1818453/4bb0e474-7005-11e3-882d-6ebe67ac65ce.png)