cvs pull from krasimir and ross, mostly hooks

  Move buildable, cc-options, ld-options, frameworks and hidden-modules
  fields into BuildInfo, so they can be overridden with local info.
  As a consequence executable-modules is replaced with hidden-modules.
  Perhaps other-modules would be a better name.

  No longer expect a name field at the head of the library stanza --
  it's redundant, and the pretty printer can't produce it.

  Another way to manage the mapping of component names to BuildInfo's
  would be to use the filesystem, i.e. look for <package>.buildinfo,
  <exename1>.buildinfo, <exename2>.buildinfo, etc, each parsing as a
  single BuildInfo.

  Change the postHook types

  Query system for "c:\Program Files"

  Add shell32 to extra-libs under Windows. It is required because
  SHGetFolderPath is called from Distribution.Simple.Configure now.