Add /etc/sysconfig/blackbird

* Implement "--pid_file PID_FILE" ("-p PID_FILE") option
* sysconfig/blackbird in defaults.cfg out for pid_file option
Updated CHANGELOG
Change URL private -> public
Move some plugin to RPM package.
Move plugin/redis.py blackbird -> blackbird-redis
Implement Timer context
float -> str(round(TIME, 4)) in Timer
Add --ignore-plugindir option.

* If you give this option, blackbird doesn't check to exist plugin dir
* This option is one for blackbird developer.
Change option delimiter '_' -> '-'

* --debug_mode -> --debug-mode
* --pid_file -> --pid-file
Implement thread pool.

* This means that blackbird can restart dead thread.
zabbix_sender plugin doesn't send empty data.
Refecter main loop sr71.py.

* remove unnecessary variable
* remove print debug...
* output Queue length to log file
Update blackbird version 0.2.0-1
Change logic of Timer context.

* if diff is < 0: diff = 0
* Rifecter calculating seconds, mili-seconds
Implement DescoveryItem
Merge branch 'master' of github.com:Vagrants/blackbird into development
When you set debug_mode, logger output stdout.
Implement BlackbirdError object.

* When an error occurs in your plugins, you should raise this error.
Implement BlackbirdError

* Changed error object name BlackbirdError -> BlackbirdPluginError
* Implement BlackbirdError
Implemente LLD thread.

If plugin module has "build_discovery_items" method,
blackbird create new thread for LLD and starts this.