Header of the proteins for search engines

[ypriverol]

@husensofteng the header of the proteins should be modified to be understood by SEARCH engines. SearchGUI don't understand the ENSEMBL ids. We probably need to move to the following header (
https://github.com/compomics/searchgui/wiki/DatabaseHelp#non-standard-fasta):

>generic[your tag]|[protein accession]|[protein description]

or 

>generic[your tag]|[protein accession]

Note that [your tag] can be empty.

Examples:

>generic_contig-535081|AC:123132|Hypothetical protein
>generic|AC:123132|Hypothetical protein
>generic|AC:123132