clean up serialise

expose the api functions as desired, and hide the non api functions
(avoids name spacing issues)

this exposes a nice little function kowhai_str_to_path() to essentially
de serialize a path which is quite useful (its counter part to serialise
a path exists, but is not exposed as I am not sure it has much use at
this time)
oops fix tabs space painfulness
fix formatting of jason array

arrays should have opening & closing square brackets, ie [], and also
require elements to be separated by commas.
http://www.json.org/

the up side of this is the node serialize output can be directly loaded
into python by cut and paste and forms a valid object (as would any well
formatted jason I guess, but this works for the node serialise now)
Merge pull request #34 from othane/node_serializer

adds a new [de]serialize method for nodes only
Merge remote-tracking branch 'djnewton/master'