Added keyword arguments mean and std to Field.power_synthesize. Bug fixes in Field, SmoothingOperator, LMSpace and Space.

Switched from `about` to keepers logging.

Removed NIFTy 2 files that have not been ported so far.

See merge request !31

Removed NIFTy 2 files that have not been ported so far.

Smooth operator



See merge request !30

# Conflicts:
#	nifty/spaces/space/space.py

Corrected bugs in the distance_array functions of lm/gl/hp space and in HPLMTransformation and LMHPTransformation

# Conflicts:
#	lm/__init__.py
#	lm/nifty_lm.py
#	rg/nifty_fft.py

- Remove mmax. Now, lmax == mmax
- Create index and l-number on the fly

- Cython extension to return the correct l-number for an index

Revised SmoothOperator implementation.



See merge request !28

- Move kernel construction to after transform
- Use d2o.arange for distance_array method in HPSpace and GLSpace

-> A Field on a PowerSpace can now be initialized with a spectral function.