Add agent listen port as a config option.
Always set a ListenPort value for agent.
Doc specific to listener_port attribute is unnecessary.
Set foodcritic to ignore FC017.
Merge pull request #114 from benpatterson/master

Explicitly set ListenPort value for agent.
Web template use empty variable for log name
Fix #116
Fix #117
Use vagrant-omnibus to install the latest Chef omnibus version

This requires the plugin vagrant-omnibus, to install run
```
$ vagrant plugin install vagrant-omnibus
```
Document how to install vagrant-omnibus plugin
Fix #118
Merge pull request #119 from lflux/master

Use vagrant-omnibus to install the latest Chef omnibus version
Timeout attribute for server
Merge branch 'master' of github.com:laradji/zabbix
include yum::epel for building on centos

Fping and iksemel-devel are in EPEL, we need to make sure it's activated before installing them.
Merge pull request #121 from lflux/master

include yum::epel for building on centos
Initial support for agent registration and update. Requires more testing.
Fixed foodcritic errors
Update zabbixapi chef_gem resource to use v0.6.3 so that we can use Zabbix server 2.0.9
Better error logging and fix bug whereby group would not be created.