ENH: Implement dump(N) to return first N frames of data.
TST: Add tests for dump.
PERF: Reinstate a custom dump for SingleNode.
typo : Readme.

Another typo :)

Best.
Merge pull request #148 from sciunto/patch-1

typo : Readme.
Merge pull request #147 from danielballan/dump-N

Implement dump(N) to return first N frames of data.