Moved path/file/URL functions for export files to a module.
gzip all exports by default.
Removed the lemmata.sort_key column.

The intended use for this column was for specifying the sort order of
lemmata in order to emulate appropriate dictionary order wherever this
deviates from lexical string sorting. In practice it has not been used,
e.g. it is not used when sorting lemmata for end-user presentation. In
the PROIEL data set only the Gothic Bible has data in this column (with
page and column numbers from Streitberg's dictionary) and this
information is duplicated in lemmata.foreign_keys.
Removed the lemmata.full_gloss column.

The intended use for this column was for specifying the a longer gloss
of the lemma, in contrast to short_gloss, which was intended for a short
gloss that could be presented as an interlinear gloss. Only support for
short_gloss was ever implemented in the application, and this column is
entirely unused in the PROIEL data set.
Renamed the column lemmata.short_gloss to lemmata.gloss.
Updated changelog and version to 1.1.0.