change default seek of signature algorithm in run4
Merge branch 'master' of github.com:pylayers/pylayers
- Modify ntheta/nphi to Nt/Np (from Fpatt)
- bug fix default Gauss pattern
- bug fix in polar
- bug fix in locbas (self.tang => self.tangl)
- improvement in plotd
- add plotad to vizualize Phi vs delays
- eval now pass a tangl and rangl to ctilde
- add a backtrace argument to run4 to allow visiting nodes already
  visited(experimental)
minor bug fix
Merge pull request #198 from niamiot/master

Bug fix in antenna rotations + new Tchannel visualizations.