bugfix - test_bug840 revealed that the recently included external/signal/bilinear.m behaves different from the matlab version. Moved bilinear to signal/private.
Merge branch 'hotfix' of github.com:oostenveld/fieldtrip

git-svn-id: svn+ssh://svn.fcdonders.nl/home/svnroot/fieldtrip/trunk@7684 0cf7c7f0-3615-4144-b4e6-68da3bce3cd0
Merge branch 'master' of github.com:fieldtrip/fieldtrip