Fixed LoggedBuildContextTidier (replace "build" object with "buildID")

Fixed instanceof comparison (wrong namespace) and add correct object to 'build' context in logger. 

It now correctly replaces the 'build' context in log entries, preventing logs to be unreadable.

Before:

```
[2013-11-12 22:17:59] BuildLog.INFO: RUNNING PLUGIN: php_code_sniffer {"build":"[object] (PHPCI\\Builder: {\"buildPath\":\"/home/elkangaroo/dev/workspace/php/PHPCI/PHPCI/../build/project1-build7/\",\"ignore\":[\"cache\",\"config\",\"dev\",\"vendor\"],\"quiet\":false})"} []
[2013-11-12 22:18:12] BuildLog.INFO: PLUGIN STATUS: SUCCESS! {"build":"[object] (PHPCI\\Builder: {\"buildPath\":\"/home/elkangaroo/dev/workspace/php/PHPCI/PHPCI/../build/project1-build7/\",\"ignore\":[\"cache\",\"config\",\"dev\",\"vendor\"],\"quiet\":false})"} []
```

After:

```
[2013-11-12 23:16:50] RunCommand.INFO: RUNNING PLUGIN: php_code_sniffer {"buildID":"11"} []
[2013-11-12 23:17:05] RunCommand.INFO: PLUGIN STATUS: SUCCESS! {"buildID":"11"} []
```