sync code with internal version

	- fix compilation on Mac OS X
	- add doc directory and split README
	- add 'normalize' to Makefile target
	- add automatic mode to 'twixtool'
	- make 'poisson' tool use dims 1 and 2
	- add option to 'rsense' to scale output
	- parallelization for 'cc' and 'homodyne'
	- rename octave viewer 'view.m' to 'octview.m'
	- use periodic boundary condition in Walsh's method
	- change default tolaerance for CG to 1.E-3
	- add 'md_next' and 'md_circ_ext2' functions
	- fix divide-by-zero for CG without regularization
	- other minor changes and enhancements