Cabal: bump version to 0.4.0.1
Httpd: minimize imports
Httpd.loopIO: forget result of looped action
Cabal: buildExamples flag for conditional building of example
Cabal: version bounds for network
Cabal.Source-Repository
Httpd: explicit and qualified imports

This anticipates network-2.4.
Cabal: allow network-2.4