add table_to_delim_string and table_to_tab_string

I don't like here-docs so I made these so I could replace some.
use table_to_tab_string instead of here-docs
use TestObjGenerator instead of more-manual creation
Expanded CreateCrossSampleVcf test case to cover the model_group interface as well as builds interface
Merge branch 'master' into gb_master
fixed documentation (L17), added support for empty CN files (L288, L332-341) and empty Regions-to-exclude files (L348-356)
Merge branch 'master' of ssh://git/srv/git/genome
add BuildClump object
update expected output due to TestObjGenerator changes
whitespace
use TestObjGenerator instead of more-manual creation
assume required_params are always inherited

Assume required_params are always inherited so we can avoid the SUPER
boilerplate in all subclasses that add required_params.
Merge branch 'master' of ssh://git/srv/git/genome
Merge branch 'master' of ssh://git/srv/git/genome
Fix the test now that UR properly filters strings for in-memory objects

Previously, UR::Object::Index used mumeric comparisons when filtering objects
already in memory.  The test was rigged to use dates in different years so
the numeric comparison just happened to work.

It now really filters out dates even at 1-day resolution
no more here-docs!
separate data from presentation by using table_to_tab_string
suffix doesn't seem to actually matter
extract data into method
make models earlier