Bug 2246 - (Partial) Label printing doesn't work with Unicode characters

Bug 2246 - (Partial) Label printing doesn't work with Unicode characters

This patch provides a very partial fix for this bug in that it reduces
the number of pdf generation failures due to a "wide character" error.
It does not ensure that all unicode characters will print correctly as
this is dependent upon many other issues mentioned in this bug and
various posts to the developer list.

What this code does is test to see if the pdf stream is utf8 encoded
and if it is, explicitly declares it to be so. Unicode chars will still
print incorrectly, but the pdf will be created and should open properly
in whatever pdf reader.

You may test this by adding any character with a diacritical to the
title of a bib and then attempting to generate a label pdf with the
title of that bib. Before the patch is applied the resulting pdf
should contain an error mentioning a wide character issue. After the
patch is applied, the pdf should be valid.

No documentation changes are necessary as a result of this patch.

This patch should be backported to 3.2.x.

Signed-off-by: Ian Walls <ian.walls@bywatersolutions.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>