In _parse_cigar, relaxed a sanity check that resulted in death on attempt

to fetch ungapped_features from DNA-PEP transcript_supporting_features
(due tothe presence of Insertions that are non modulo-3 in length, which is
common for introns).

modules/Bio/EnsEMBL/BaseAlignFeature.pm

@@ -381,7 +381,8 @@ sub _parse_cigar {
             "allowing 1 or 3 ");
     }
 
-    if( int($mapped_length) != $mapped_length ) {
+    if( int($mapped_length) != $mapped_length and
+        ($piece =~ /M$/ or $piece =~ /D$/)) {
       throw("Internal error with mismapped length of hit, query " .
             "$query_unit, hit $hit_unit, length $length");
     }