Edited Feature: !help command [12728]

Pykd has no !help command.

When trying new plugins, this is one of the first things I do. How else should I find out how the plugin works? BTW: the help function of Python is one thing I really like.

Actually, the output needn't be much:
- print the version number of pykd, so that I can figure out whether I'm using the latest version
- give me a link to the main site (pykd.codeplex.com)
- if the commands are not displayed, give a link to the commands

Sample output which would fulfill my needs:
```
0:000>.setdll pykd.pyd
0:000> !help
pykd - Python Extension for WinDbg - 32 bit
Version 0.2.0.27
Check http://pykd.codeplex.com for updates
Available commands:
!pycmd - python command prompt, use quit() to exit
!py help - list of functions in the API, see also http://pykd.codeplex.com/
!py samples - list of samples provided with pykd
!py path\script.py [<param> [ ...]] - run a python script
```