Updated to handle NanoSeq

[jenniferliddle]

Change read2tags to allow reading from read 1 and writing tags to read 2 (and vice-versa)

[srl147]

Jennifer correct me if I'm wrong the way you removed the dependancy on samtools was to simply switch the tests to using sam files, which don't need to be processed with samtools

[jenniferliddle]

Absolutely correct. I deemed that to be the simplest solution, and better for future additions and tests.