Early version of M-SSA. Somehow works...
Unbreak the usual SSA
Add lrr and rforecast (L-forecast) for mssa
First cut of complex SSA
Use proper number of eigenvalues for complex SSA
Speedup
Speedup hmat-building in `decompose.mssa.eigen'
Fix hmat-building in `decompose.mssa.svd'
Add support for unequal series lengths for MSSA. Along the lines:

1. Introduce new kind of "elementary series": series list. Overload the arithmetic ops on it
2. Streamline the hanlding of attributes
3. Get rid of .slength
4. Make sure the common methods do no decisions about e.g. contents
5. Cleanups here and there
Implement fixup for .apply.attributes
Add k-forecast
Document rforecast.mssa
Swap row and columnt
Properly handle neig argument for decompose.mssa.eigen and decompose.cssa.eigen
Fixes for automatic svd methods for MSSA and CSSA
Properly conjugate for complex LRRs
Save implicit class into Rssa object
Move complex SSA to separate file
Cleanup
Add some plots with MSSA along with nifty slicing