Makefile: install locale files to $localedir
__fish_print_packages: add support for zypper

Closes #1787.
abbr/web_config: support space-delimited abbreviations

Support for space-delimited abbreviations was added to the expansion
parser in fbade198; this commit extends that support to the user-facing
tools, and documents the space-separated behaviour. Equals-delimited
abbreviations are expected to be removed before the next release.

Work on #731.