Migrating to persistent-1.2 and esqueleto. Still broken.

TODO:
- The tagQueryRejectTags field does not affect.
- selectTaggable{,Source} does not return the "taggable" values,
  only returns the key of "tagging" table.
returns the "taggable" values.
well type constraint
support reject tags query.
add tagQueryWhere
additional query
Bump the dependency for esqueleto to 1.2.2
Merge branch 'esqueleto-1.2'
Bump version to 0.3.0