Add title attribute for skins/modes hiding the actual button text

Conflicts:
	skins/larry/templates/messagepart.html
Add Vacation date range feature for servers without the sieve 'date' extension (using regexes)
Fix "Illegal offset type" error (#1489985)
New gearman driver for password plugin
Collapsible (and iconized) folders tree in folder manager (#1489648)
Don't overwrite the whole fieldmap so autocomplete names are resolved correctly
Merge pull request #203 from mdamt/gearman-password

New gearman driver for password plugin
Merge pull request #202 from jacoblister/master

Add Vacation date range feature without the sieve 'date' extension
CS fixes after PR merge
Updated changelog and CS fixes after PR merge
Code improvements + added tests for vacation date regexps handling