.......... [ZBXNEXT-826] updated release version [2.4.0rc1]; updated API version [2.4.0]

git-svn-id: svn://svn.zabbix.com/trunk@48840 f4e7fd02-d210-4e34-a1e0-d4093fb66cc2
.......... [ZBXNEXT-826] Windows precompiled agents [2.4.0rc1]

git-svn-id: svn://svn.zabbix.com/trunk@48841 f4e7fd02-d210-4e34-a1e0-d4093fb66cc2
.......... [ZBXNEXT-826] fixed ChangeLog

git-svn-id: svn://svn.zabbix.com/trunk@48844 f4e7fd02-d210-4e34-a1e0-d4093fb66cc2