Simplify `trac.loader` a bit by:
* making use of the fact that SetupTools is now a mandatory dependency, and * dropping support for plugins not using the `trac.plugins` entry point. Also, load `.py` source (single-file) plugins after Python eggs (closes #4383).
Authored by: cmlenz 2007-01-25
Parent: [r4632]
Child: [r4634]
