Int overflow in creating jemultiplexer_out_stats.txt on slightly larger genomes

[Cleiti]

Bug in codefile: /org/embl/gbcs/je/jemultiplexer/AbstractJemultiplexer.java
When calculating total reads to write lines "Processed reads" and "Assigned reads" into .txt output, the variables are declared as int.
The amont of processed reads is small enough on Yeast (SacCer) genome, but goes into into overflow on larger genomes, such as Horse.