check for merge conflicts

coloring doesn't seem to work on Travis (it doesn't harm either), but
should on a plain Linux or Mac shell prompt

build/run_tests.sh

@@ -3,10 +3,28 @@ xvfb-run ctest
 PROC_RET=$?
 
 if [ "$PROC_RET" -ne 0 ]; then
-killall Xvfb
-xvfb-run ./mtest
+  killall Xvfb
+  xvfb-run ./mtest
 fi
 
+# Searching for merge conflicts, by searching for the begin/end markers.
+# Searching for the middle marker '=======)" won't work though as that is
+# used elsewhere too.
+# Haven't found a way without using an intermediate temp file.
+rm -f /tmp/$$ # Cleanup, just in case of an older leftover
+find ../.. -type f ! -name `basename $0` -print0 |
+  xargs -0r egrep -n '<<<<<<< HEAD|>>>>>>> .*' |
+  tee /tmp/$$
+if [ -s /tmp/$$ ]; then # File not empty
+  PROC_RET=`expr $PROC_RET + 1` # Store the error
+  printf "\033[31m" # Set color to  (doesn't work on Travis though)
+  echo
+  echo "problem with a merge conflict"
+  echo
+  printf "\033[0m" # Reset color
+fi
+rm -f /tmp/$$ # Cleanup
+
 #pwd == build.debug/mtest
 cd ../../vtest
 xvfb-run ./gen
@@ -22,4 +40,4 @@ cd -
 #curl -F zip_file=@$REVISION.zip  http://prereleases.musescore.org/test/index.php
 #echo "Test results: http://prereleases.musescore.org/test/$REVISION/"
 
-exit $PROC_RET
+exit $PROC_RET