Switched to Bats-core as a submodule

Can't use the official v0.4.0 release, since our tests rely on a change
that was made after the release of v0.4.0.

This code currently uses an unversioned commit of the bats-core repo, we
will switch to a supported version once it has been released, e.g.
v0.4.1.

test/bash_it/bash_it.bats

@@ -6,9 +6,11 @@ load ../../lib/composure
 function local_setup {
   mkdir -p "$BASH_IT"
   lib_directory="$(cd "$(dirname "$0")" && pwd)"
+  echo "Bi : $BASH_IT"
+  echo "Lib: $lib_directory"
   # Use rsync to copy Bash-it to the temp folder
   # rsync is faster than cp, since we can exclude the large ".git" folder
-  rsync -qavrKL -d --delete-excluded --exclude=.git $lib_directory/../.. "$BASH_IT"
+  rsync -qavrKL -d --delete-excluded --exclude=.git $lib_directory/../../.. "$BASH_IT"
 
   rm -rf "$BASH_IT"/enabled
   rm -rf "$BASH_IT"/aliases/enabled