Added support for new CIGAR characters, may need to be re-visited again

This quick fix is to improve compatibility with newer (v1.4-r985) samtools

ERROR (CigarRoller.cpp:118): Parsing CIGAR - invalid character found with parameter  and [number]

handles both '=' and 'X' characters as 'match' which seems to be ok
according to samtools specs,
but should be using a better handling in a future