Rename ignore_directories to ignore_paths and add build_everything setting

The build_everything setting lets you specify a path so that if any file starts with that path then all modules will be built.    This is sometimes used for global settings files that do not have maven dependencies for all modules but should still trigger a build of everything.

Also fix some logic when sending email about changes in ignored_paths.  Ignore_directories was renamed to ignored_paths because it is used a prefix check against changed files instead of a directory prefix
this stub could probably move into a before filter for the whole file.