#15 Support for PassEnv and SetEnv

[Don Mahurin]

This patch adds support for Apache style SetEnv and
PassEnv.

Its use is to pass extra information to a called cgi.

To do this, the internal cgi env array, previously used
only for server env's is made to grow as needed.
PassEnv and SetEnv provide a conf file interface to add
other env's.

[Don Mahurin]

boa PassEnv/SetEnv patch