Added Extended Eof (EEof) 

Dear Dr. Andrew Dawson,

My friend Dileep and myself added support for "Extended Empirical Orthogonal Function Analysis" as we discussed so long back with respect to issue #12 .

We added EEof class methods only which are all we tested using cdms module (via UV-CDAT) and results are getting correct. Other Eof class methods will be used by the users in case of need, because we inherited Eof super class to EEof sub class, in case of need by the users.

I never used iris module, so I couldn't add full fledged support for it. But you may fix it where I mentioned TODO tag (create time axis iris syntax) in iris module's EEof Class constructor.

We tested EEof analysis by reproducing the same results given in the paper "Kikuchi K, Wang B, Kajikawa Y (2011), Bimodal representation of the tropical intraseasonal oscillation. Clim Dyn. doi:10.1007/s00382-011-1159-1 [Link](http://link.springer.com/article/10.1007/s00382-011-1159-1)"

We used "A. Hannachi, 2004, A Primer for EOF Analysis of Climate Data, Department of Meteorology, University of Reading, Reading RG6 6BB, U.K. [Link](http://eros.eas.gatech.edu/eas-8803/lectures/EOFs/eofprimer.pdf)" documentation to reconstruct input matrix as extended input matrix to  conduct Eof analysis on it, with respect to input lag window.

With Regards,
Arulalan.T