angles: some optimisation of asep()
command_line: read number from string unformatted

* command_line: read number from string unformatted:
  * prevents issues when reading a real without a decimal point
Added more double-precision float dummy variables (10-19)
Added routine poisson_prob() to compute Poisson probabilities

& Added routine poisson_prob() to compute Poisson probabilities:
  * probability of k events occurring in a fixed interval for a known average rate lambda