Rely on the Compara-defined descriptions of homologies

I have defined the plain-text descriptions of the homology types in the Compara Homology module. It simplifies the webcode a lot :) !

I've also changed the call to the HomologyAdaptor to only get orthologues / paralogues depending on the view

Finally, I had to define two descriptions for the orthology types because they're only displayed as "1-to-1" in the table, but a true description should rather be "1-to-1 orthologues"
So the table of homologues uses %PLAIN_TEXT_WEB_DESCRIPTIONS, whereas the alignment page uses %PLAIN_TEXT_DESCRIPTIONS

# List of orthologues
http://enssand-01.internal.sanger.ac.uk:9073/Homo_sapiens/Gene/Compara_Ortholog?g=ENSG00000139618;r=13:32315474-32400266
#Alignment of orthologues
http://enssand-01.internal.sanger.ac.uk:9073/Homo_sapiens/Gene/Compara_Ortholog/Alignment?db=core;g=ENSG00000073910;g1=ENSVPAG00000010883;r=13:32031300-32299122
# List of paralogues
http://enssand-01.internal.sanger.ac.uk:9073/Homo_sapiens/Gene/Compara_Paralog?g=ENSG00000073910;r=13:32031300-32299122
#Alignment of paralogues
enssand-01.internal.sanger.ac.uk:9073/Homo_sapiens/Gene/Compara_Ortholog/Alignment?db=core;g=ENSG00000073910;g1=ENSVPAG00000010883;r=13:32031300-32299122