Zabbix

 - added frontend-side support of quotes and triger expression validation (Eugene)

 - merged rev. 4305:4307 [improved trigger expression syntax and validation]
 - merged rev. 4329:4331 [more support for quotes in key parameters]
 - merged rev. 4344:4346 [minor improovments]
 - merged rev. 4431:4432 [added availability of using ":," character for key]