Function Make-Cigar-Operation

Part of:

package elprep
( make-cigar-operation < table > < cigar > < i > )
Parse a CIGAR length + operation from position i in the cigar string.
Return a cons cell with upcase character + length, and a next position in the cigar string.
See http://samtools.github.io/hts-specs/SAMv1.pdf - Section 1.4.6.