Log Message:
increase BUILDLINK_ABI_DEPENDS.icu due to so change from 49 to 50.

Also bump PKGREVISION for a few packages using it.

The packages I did this for:
net/yaz
lang/parrot
misc/openoffice3 (where I noticed the run-time failure due to missing shared library)
www/webkit-gtk
sysutils/open-vm-tools
inputmethod/ibus-qt

I didn't do this recursively or for all packages using icu
since I didn't know if they used the shared library directly,
some use was optional. The list of packages I didn't touch:
devel/devhelp
databases/idzebra
databases/sqlite3
devel/gnustep-base/
finance/gnucash
games/openttd
graphics/shotwell
lang/mono
meta-pkgs/boost
misc/calibre
misc/libreoffice
news/tin
textproc/php-intl
www/deforaos-surfer
www/epiphany
www/liferea-current
www/midori