SEQWARE-1909

Allow workflow launcher to intepret null parameters as empty string. It
looks like we have other behaviour that relies upon null parameter
values, so this cannot be a change at install-time (at schedule time,
the parameter is not necessarily specified)
SEQWARE-1901

Allow launching with only an override (or really, without a bundle ini
even)
Merge pull request #220 from SeqWare/feature/ini_file_changes

Feature/ini file changes