Re-organize code for callsnp.go and main/isc.go:
- Move functions ReadReads(), ProcessReads() to from main/isc.go to callsnp.go
- Take out the code for read alignment phase (with goroutines) from main/isc.go to a new function AlignReads() in callsnp.go.
- Modify function CallSNP() and create a new function CalcSNPQual() in callsnp.go to prepare for SNP quality calculation phase (with goroutines).
Modify function WriteSNPCalls() in callsnp.go
- Rename several functions in callsnp.go.
- Separate function FindSNP() to process each end.
- Remove reverse complement parts from ReadInfo data structure and move their calculation to function FindSNP().
make several changes