version 0.1.0: first release
version 0.1.1: fix a bug in NGS.CNV function
version 0.2.0: substantially revise functions in msscan_tools.R to fix several bugs in 
               identifying the exact locations of change points
version 0.3.0: add functions for processing SNP array data and SCNA calling pipeline
version 0.3.1: 1) improve baseline computing function
               2) change the name of cnv.call.seq to cnv.call
               3) modify diagnosis.cluster.plot
               4) fix a bug in merge.segments to make sure maxL is properly calculated
version 0.3.2: 1) change compute.baseline to make log2ratio dimension more robust
               2) automatically decide maxL and ref.num.probe as the 1/100 the data points
                  if the user does not choose one
               3) add seed option to the functions using resampling strategy for 
                  reproducibility
               4) correct some bugs in document examples
               5) change the function name merge.segments.chr and merge.segments to 
                  merging.segments.chr and merging.segments to avoid confusion with the
                  function merge with regard to S3 method nomenclature
               6) revise the vignettes
version 0.3.3:
               1) add function for GC content adjustment
               2) add function for manual baseline adjustment
               3) update NGS.CNV and SNP.CNV to include GC adjustment functionality
               4) update the vignettes
version 0.3.4:
               1) update reference
               2) move some big data files to saasCNV website to reduce the size of 
                  the package
               3) update documents