#14 Add extra env variables for CGI

[Karol]

I have some web applications (for example mythweb from the MythTV project) written in PHP that require extra environment variables to run. I have also noticed that other people on several web-forums were looking for a similar functionality in yaws. So, here is a patch that adds an extra section in the server definition part of the yaws.conf file with the format:
<extra_cgi_vars dir='a path to some scripts'>
'var' = 'val'
...
</extra_cgi_vars>

The extra variables are added to the environment just before a CGI script is to be run in the given directory.

The patch was created against a 1.81.

[Karol]