output formats

[cbroeckl]

thanks for the work on this - i am excited to give it a go! noticed a few issues with the output format:

1. msp format does not add ion annotations, even when the --annotation flag is used.
2. i would request that there are two additional bits of information exported in msp and mgf format a. molecular formula of the parent molecule (not ion) b. precursor accurate mass, or monoisotopic molecular weight of parent ion.