annotate_peptides function does not show error for mismatching identifiers

[MiguelCos]

The for loop in the function will stop if it doesn't find a match between protein identifiers and the fasta file.

It doesn't show an error if this is the case. This should be corrected.

[MiguelCos]

The error was due to the format of the list containing the fasta.

Just test in annotate_peptides if the protein sequence is not a list (it should be string) and throw an error message ("Use as.string = TRUE in read.fasta()......")