Problem 967. Split a string into chunks of specified length

Given a string and a vector of integers, break the string into chunks whose lengths are given by the elements of the vector. Extra characters leftover at the end should be dropped. Example:

break_string('I seem to be having tremendous difficulty with my lifestyle',[4 1 5 22])

should return a 4x1 cell array:

ans = 
  'I se'    'e'    'm to '    'be having tremendous d'