Create a knob for confexport to do repository/recipe/module-based exports

[blee]

confexport should be able to do repository, recipe, and module-based exports.

The situations that each style optimizes for should be documented.

confsync must be updated to understand the various types of exports.

[blee]

(In [363])
Enable repository, recipe, and module-based exports.

See #32

[blee]

(In [364])
Some cleanup and better error handling for new export styles in
confsync and confaudit.

See #32

[blee]

(In [365])
Cleanup for new export styles in conf_fetch, conf_fetch_file, and
conf_export.

See #32

[blee]

(In [366])
Add man page notes for CONF_EXPORT_WORK_PATH and CONF_EXPORT_STYLE.

See #31, #32

[blee]

(In [367])
Merge new export styles from trunk into 1.9 branch.

Fixes #32