handle specifying variable format with #, comments

[willkg]

http://www.gnu.org/software/gettext/manual/html_node/PO-Files.html#PO-Files

The comment lines beginning with #, are special because they are not completely
ignored by the programs as comments generally are. The comma separated list of
flags is used by the msgfmt program to give the user some better diagnostic
messages. Currently there are two forms of flags defined:

Then it goes on to talk about variable format flags. We should support those flags to build variable tokenizers for those strings.

[willkg]

Probably want to wait on this until we support many/most of the gettext variable formats.