Update .htaccess

Delete a bugfix for PHP4, because the current version requires at least PHP 5.2.1. The case thus never occurs.
Avoid session timeouts with memcache backend as proposed by D. Carter via users mailing list
Merge branch 'master' of github.com:roundcube/roundcubemail
replaces smart quotes with regular quotes. Fixes improper doctype declarations in html emails
Merge pull request #93 from Dennis1993/patch-2

Remove old bugfix for PHP4
Merge pull request #98 from rodrigo-castillo/master

replaces smart quotes with regular quotes
Fix priority selector when open in new window (#1489257)
Better check for priority header
Fix parsing of links with ... in URL (#1489192)
Updated Changelog
Fix identity-selection using Return-Path headers (#1489241)
Updated changelog