Accept empty config file or one with only comments
Add a test for parsing an empty INI file.

This is the first test of this parser.  Adding more is long overdue.

Signed-off-by: Magnus Therning <magnus.therning@evidente.se>
Merge in changes from Mikolaj.

Signed-off-by: Magnus Therning <magnus.therning@evidente.se>

Conflicts:
	tst/ReaderI.hs
Remove unnecessary module import.

Signed-off-by: Magnus Therning <magnus.therning@evidente.se>