Allow underscores in trusted hosts

Underscores are valid characters in domain names, so don't prohibit them in trustedHosts[].
Also the domain name should be validated before creating the list with an invalid entry.
moved previously hardcoded in template Settings menu element into proper Menu class
refs #6296 maybe we can detect number of rows matched by the UPDATE query, by using Mysql client flags  in both Mysqli and PDO
Fixing bug found by tests
Adding unit test to check that rowCount() really returns matched rows and not only affected/updated rows
Add extra docs for core/Auth.php and make sure Registry has docs generated for it.
Let's run all MYSQLI tests on PHP 5.4, because on PHP 5.3 there are too many skipped tests which would decrease code coverage for MYSQLI adapter for no reason.
Tweaking Auth docs some more.
fix plugins test
The MYSQL_ATTR_FOUND_ROWS attribute only works as a connection option, and cannot be set after mysql connection is established. source: http://stackoverflow.com/a/18684115/3759928 - this should fix the build!
lat+long show differently on mysqli (more precision)
Fix typo when parameters were moved to constructor config
Merge pull request #6304 from stackcoder/patch-2

Allow underscores in trusted hosts
Merge pull request #6323 from piwik/6296_alternative_fix

Mysql return rows count found in an UPDATE rather than rows modified
make filename shorter less than 144chars
Rename test_PivotByQueryParamTest_test_PivotBySubtableDimension_CreatesCorrectPivotTable_WhenEntireHirearchyIsNotLoaded__Referrers.getKeywords_week.xml to test_PivotByQueryParamTest_test_PivotBySubtableDimension_WhenEntireHirearchyIsNotLoaded__Referrers.getKeywords_week.xml
Merge pull request #6322 from mgazdzik/moveSettingsTabToMenu

moved previously hardcoded in template Settings menu element into proper menu class
Removing disablePurge hack in tests, as this should not be needed anymore
refs #6116
Merge pull request #6338 from piwik/fix_filename

Fix  git fatal failed to stat File name too long
Merge pull request #6340 from piwik/remove_disablePurgeHack

Removing disablePurge hack in tests, as this should not be needed anymore