Added x3 tests to Jamfile
Added test for recently fixed sequence attribute consistency bug
Fix for sequences with only one element producing attr

If in a sequence only one element produces attribute, then make whole
sequence to produce that attribute,rather than wrapping it into
fusion::deque. Not doing so breaks alternative<> parser, when such
sequences are on left and right side of it, because it then generates
variant attribute over fusion:deque<> attributes, which is not
what it is supposed to do. Plus it breaks traits::move_to when both
source and destination are single element fusions sequences. Hence this
fix to put everything back to normal for this edge case.
Merge pull request #8 from redbaron/fix-one-element-seq

Fix one element seq