% v=hash_get_value(hs,key,h)
%   Returns value of the hash hs for a given key
%   If key is not found and h = 1 than the 
%   result is an empty hash. If h = 2 - result is 0.
%
%   Input:
%       hs  - hash clas
%       key - key value
%       h   - type of returned value if key is not
%             found. 
%
%   Output: 
%       v   - value in hs for that key
