[88] Guidelines for Node label formatting

[prmtl]

Reported by maris.ju...@gmail.com, 2013-12-12T23:06:44Z

It seems that formatting of the label string supplied to Node constructor
is very sensitive. I had working code that was producing svg with this kind of string for node labels:$GUID__/ffb73e1c-7495-40b3-9618-9e5462fc89c7 . Now I think I have new pydot version and the code does not work:
Warning: /tmp/tmpxa46du:5: ambiguous "-40b" splits into two names: "-40" and "b". If I remove this string, the problems continue, something about newline at the end of the remaining string (as I read on the forum somewhere).

What are the rules for the label string?
Thank you.
From: https://code.google.com/p/pydot/issues/detail?id=88

[prmtl]

Problem mentioned in the bug will be fixed in #37.
Also some info about labels could be found in http://www.graphviz.org/doc/info/lang.html

Side node: we need to add docs for pydot-ng, tracked in #38