Added function for multiple EM iterations.
Added function for multiple EM iterations.

multi_em() is for combining the results of multiple EM runs. This function
calls run_em() a specified number of times and keeps the results from each
run. After the last EM run has converged the results are averaged and returned
the same way run_em() returns results (tuple(Vector of estimated proportions,
matrix of read probablities per haplogroup)).

svohr/mixemt,svohr/mixemt,svohr/mixemt