Item13023: Unit tests for Bootstrap

Not everything passes yet:
 - Core has issues with lighttpd,  which always sets a SCRIPT env
   variable even for short URLs.
 - TestBootstrapPlugin attempts to address it but still breaks, and
   breaks other stuff.

We need to gather the common ENV settings for our supported web server
configurations, so that this can be improved.

These tests should be moved into core once this is all worked out.