a) add a new function
hra_core.io_utils.number_of_lines(_file)
get number of lines of a text file

b) add a new statistic, asymmetry statistic  which 
returns 1 if conditions for asymmetry are fulfilled otherwise 0,
asymmetry conditions:
C1d > C1a and C2a > C2d and Ca > Cd
implemented as a class
hra_math.statistics.statistics.AsymmetryStatistic

c) change short name of poincare plot parameter (-d) into (-data_file),
package hra_math.time_domain.poincare_plot.poincare_plot

d) add a very specialized function:
hra_math.model.utils.prepare_data_arrays(_file, _headers_count, _data)
which converts (if necessary) input data array into array of arrays
use this function in 
hra_math.model.text_file_data_source.TextFileDataSource.getData(self)
hra_math.model.numerical_file_data_source.NumericalFileDataSource.getData(self)