Ideographic fullstop and comma in most Chinese fonts are centered,
while those in Japanese fonts align closer to the left. Original
compression algorithm trimed right side of the punctuation, making
fullwidth fullstop or comma in Chinese font visually unbalanced.
In worst case, it crowds together with the followed compressed
punctuation.

This patch fix the situation in the folowing way
1) make compression less stronger.
2) Trim space according to glyph bearing to font height ratio.
3) fix a memory access violation issue

Reviewed-on: https://gerrit.libreoffice.org/19517Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Norbert Thiebaud <nthiebaud@gmail.com>

Conflicts:
	sw/source/core/txtnode/fntcache.cxx

Change-Id: Icff215064e6c442fd36eac8e01b01fb6acb27594
Reviewed-on: https://gerrit.libreoffice.org/19764Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>