Fix imports for Python 3

pyModeS/__init__.py

@@ -1,3 +1,5 @@
-from util import *
-import adsb
-import ehs
+from __future__ import absolute_import, print_function, division
+
+from .util import *
+from . import adsb
+from . import ehs

pyModeS/adsb.py

@@ -18,8 +18,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
 
 import math
-import util
-from util import crc
+from . import util
+from .util import crc
 
 
 def df(msg):

pyModeS/ehs.py

@@ -17,8 +17,8 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
 
-import util
-from util import crc
+from . import util
+from .util import crc
 
 
 def df(msg):