More concise test summary info

The summary info printed after a test run has got quite long, which means more scrolling back to see actual test failure details. This pares it down a bit.

Before:

```
Test suite completed for system with the following information:
{'codename': 'Work in Progress',
 'commit_hash': '2cdbe39',
 'commit_source': 'installation',
 'default_encoding': 'UTF-8',
 'ipython_path': '/home/takluyver/.virtualenvs/ipy-3/lib/python3.3/site-packages/ipython-2.0.0_dev-py3.3.egg/IPython',
 'ipython_version': '2.0.0-dev',
 'os_name': 'posix',
 'platform': 'Linux-3.10-3-amd64-x86_64-with-debian-jessie-sid',
 'sys_executable': '/home/takluyver/.virtualenvs/ipy-3/bin/python',
 'sys_platform': 'linux',
 'sys_version': '3.3.2+ (default, Jun 13 2013, 11:56:31) \n[GCC 4.8.1]'}

Tools and libraries available at test time:
   curses cython jinja2 matplotlib numpy pexpect pygments pymongo qt rpy2 sphinx sqlite3 tornado zmq

Tools and libraries NOT available at test time:
   azure oct2py wx wx.aui

Ran 1 test groups in 3.569s

Status: OK
```

After:

```
Test suite completed for system with the following information:
IPython version: 2.0.0-dev
IPython commit : 97d2b83 (installation)
IPython package: ~/.virtualenvs/ipy-3/lib/python3.3/site-packages/ipython-2.0.0_dev-py3.3.egg/IPython
Python version : 3.3.2+ (default, Jun 13 2013, 11:56:31) [GCC 4.8.1]
sys.executable : ~/.virtualenvs/ipy-3/bin/python
Platform       : Linux-3.10-3-amd64-x86_64-with-debian-jessie-sid

Tools and libraries available at test time:
   curses cython jinja2 matplotlib numpy pexpect pygments pymongo qt rpy2 sphinx sqlite3 tornado zmq

Tools and libraries NOT available at test time:
   azure oct2py wx wx.aui

Status: OK (1 test groups). Took 3.476s.
```