Added the writing of log messages to a cache

Added the writing of log messages to a cache
 - added config param cachePath for log server
 - defaulting the cachePath under the Cake install task
@msmathers 
Maybe pull this out into its own method, so then you can just call:
```
@_cacheLogMessage logConf, stream, node, message, logLevel
```

And maybe assign the arguments to variables first so you don't have to break lines when calling `fs.appendFile()`, like:
```
cachePath = "#{logConf.cachePath}/#{stream.name}:#{node.name}"
cacheStr = JSON.stringify
  time: now
  message: message
  level: logLevel
fs.appendFile cachePath, cacheStr + "\n", (error) ->
  console.error("Error writing file", error) if error
```