* move professions out of the examples folder
* install professions into professions/library
* guard unguarded header from multiple inclusion
* load and display library professions
* update changelog
* move example professions docs from examples guide
* update dreamfort documentation
* note that professions folder has changed
* Fix bad merge
This is only necessary for multiple-selection columns, and there aren't any
with non-pointer entry types currently, but casting nullptr to non-pointer types
isn't a great idea.