Create the "SDK". for extend or hack regain
Patch to let crawler support Basic authentication.

Tested in trac, note:
 1. Setup username and password in `<PROFILE_HOME>/conf/authentication.properties`, password must be Base64 encoded, such like:
    http.www.thinkbase.com.8080.account=testuser
    http.www.thinkbase.com.8080.password=Y2hhbmdlbWU=
 2. The the spidering start url must be a protected url, such as /trac/env1/login;