This function writes a qpcrBatch out to a tab-delimited text file.
writeQpcr can be used to write out the normalized qPCR data out
to an external file.
Function creates a tab-delimited text file with three columns,
1st column = names denoting genes or primer pairs
2nd column = plate index
3rd column = normalized Ct value
References
Mar J et al. Data-driven Normalization Strategies for qPCR Data. Technical Report, 2008.