fix(livesearch): removed custom queries with ege* functions

There was a long standing todo to remove the custom queries in the
livesearch page_handler with elgg_get_entities* functions.
fix(core): prevent sql exception when metastring is interpreted as very large number in egef_metadata

Fixes #7009
fix(upgrade): Ensure that `$CONFIG` is always available to upgrade scripts

Fixes #7457
Merge pull request #7460 from ewinslow/fix-install-upgrade

fix(upgrade): Ensure that `$CONFIG` is always available to upgrade scripts
Merge pull request #7381 from beck24/7009-egef-metadata

fix(core): prevent sql exception when metastring is interpreted as very ...
fix(views): input/userpicker can now remove all users on edit

We must provide an empty input in case all users are removed. Otherwise
no value will be submitted.

Fixes #6982
fix(plugins): trigger plugin hooks when saving plugin settings

The introduction of setPrivateSetting led to failing to trigger the plugin hooks.
Only property sets result in the hooks being triggered so we return to that method.

Fixes #6820
Merge pull request #7471 from mrclay/lowfill-1.9

fix(plugins): trigger plugin hooks when saving plugin settings
Merge pull request #7470 from mrclay/6982_19_userpicker

fix(views): input/userpicker can now remove all users on edit
fix(views): Revert erroneous changes made to input/userpicker

This reverts commit 4cf113ab60f6e3c5e0d445f70fdd8cd530917642 which caused the
friends picker to stop working when there were no existing values selected.
Merge pull request #7481 from juho-jaakkola/revert_userpicker

fix(views): Revert erroneous changes made to input/userpicker
fix(i18n): Commit docs/*.mo files on release so docs can be translated

Fixes #7034
fix(upgrade): Rechecks that all annotation comments have been migrated to entities

The discussion reply upgrade had a bug that caused it to mark also the comments upgrade
as completed. This rechecks whether there still are unmigrated comment annotations left
and marks the comment upgrade as incomplete if annotations are found.

Fixes #7486
docs(travis): Added validation of translated docs sources for es language to Travis
docs(pdf): Added LaTeX build testing to Travis
fix(docs): Fixed docs syntax for the PDF builds.
Merge pull request #7489 from juho-jaakkola/fix_7486

fix(upgrade): Rechecks that all annotation comments have been migrated to entities
fix(release): Corrected release script Windows system compatibility.
Merge branch 'docs-i18n' into 1.9
chore(i18n): update translations