Add support for 0 length reads in fastq-mcf

[drsuuzzz]

fastq-mcf currently crashes if it encounters a 0 length read. #46 attempted to solve this but processing would halt when encountering the first 0 length read in the fastq file, leaving the rest of the reads out of the clipped read file.

[earonesty]

https://github.com/ExpressionAnalysis/ea-utils/pull/86