Log Message:

	Version 4.6.1 - 2014-02-02
===========================
Cleaning up some small bugs introduced with the new lsqfit.wavg. Also 
introduced an approximate but potentially much faster *fast* mode for it.

Version 4.6 - 2014-01-30
========================
The main change here is an upgrade to lsqfit.wavg.

- Somewhat incompatible change in lsqfit.wavg: When averaging arrays or dicts,
  wavg used to ignore correlations between different elements of the 
  array or dict. The new wavg takes account of all correlations between 
  different pieces of input data. wavg returns a GVar if averaging 
  a list of GVars, a numpy array of GVars if averaging a list of arrays
  of GVars, and a Bufferdict of GVars or arrays of GVars if averaging
  a list of dicts. In each case the return value has extra attributes:
  chi2, dof, Q, time, fit. The function itself also has these attributes, 
  coming from the last fit.

- gvar.mean(g) now returns g unchanged if g contains objects of type
  other than GVar. This is useful for writing functions that must work
  with either GVars or floats as arguments: gvar.mean can be used to 
  strip the sdev off of GVars where it isn't needed or wanted.

- New function gvar.asbufferdict(g) converts dictionary g to a 
  BufferDict unless it already is one, in which case it returns g.
  The keys in the final result can be restricted by adding a 
  a list of keys as a second argument: gvar.asbufferdict(g, keylist).