Adding optional hdfs and request options to "open" method

The additional parameters allow to set {"encoding":null} as option to request. As a result the returned body is a Buffer instead of a String. This makes it possible to work with binary data.
Consistent hdfs and request options for all methods

setting of a request timeout to all requests
Forward request errors

Forward request errors to caller
return request object in order to be able to stream the data
Adding optional hdfs and request options to "open" method

The additional parameters allow to set {"encoding":null} as option to request. As a result the returned body is a Buffer instead of a String. This makes it possible to work with binary data.
rebase
Forward request errors

Forward request errors to caller
return request object in order to be able to stream the data
Merge branch 'master' of github.com:artur-krueger/node-webhdfs

Conflicts:
	src/webhdfs.js
Merge pull request #3 from artur-krueger/master

Adding optional hdfs and request options to "open" method