Refactored Spaic2Solver.
Refactored Spaic2Solver.

Fixed density vs woodsaxon params problem.

- @property density_params should return bs.para describing the e- charge density.
- @woodsaxon_params.setter:
	- set them to p2d
	- compute the density params.
	- set them from p2d into bs module.

- Adds a method init, that solves a hen-and-egg problem in initializing
  quantum_numbers and density_params.

This ensure that density_params always contain a valid state with
density params.

Properties
- Spaic2Solver.radius		returns radius in spaic2_betaSpect
- Spaic2Solver.density_params	returns bs.para
- Spaic2Solver.frequencies	returns bs.frequencies

jusjusjus/spyclib