Modify the UPGMA program we wrote in class to output newick formatted
trees with sequence names instead of sequence IDs. The input to your
program is a distance_matrix.txt file and a FASTA dna_fasta.txt file 
containing the same number of sequences as the number of rows (or columns) in
the distance matrix. For example if distance_matrix.txt is

0  2  10  10
2  0  10  10
10 10 0   2
10 10 2   0

then dna_fasta.txt will contain 4 names and 4 sequences

>human
AACGTG
>chimp
ACCGTG
>mouse
GTGACC
>rat
GTGGCC

Submit the your UPGMA.py program as hardcopy in class on Apr 19th.