tsplot: warning fix, unicode fix

Unicode handling changes between 2.7.9 and 2.7.12, and
what worked transparently in the latter breaks weirdly
in the former. This patch coerces everything to unicode
for great justice.

Fix logger warning issue.

scripts/tsplot.py

@@ -5,6 +5,7 @@ import json
 import numpy as np
 import sys
 import re
+import logging
 import matplotlib as M
 import matplotlib.pyplot as P
 from itertools import chain, islice, cycle
@@ -173,7 +174,7 @@ class PlotData:
                 for i in xrange(n):
                     prefix = '' if k=='name' else k+'='
                     if vs[i] is not None:
-                        labels[i] += ', '+k+'='+str(vs[i])
+                        labels[i] += u', '+k+u'='+unicode(vs[i])
 
         except StopIteration:
             pass
@@ -190,7 +191,7 @@ def gather_ts_plots(tss, groupby):
     for ts in tss:
         key = tuple([ts.meta.get(g) for g in groupby])
         if key is () or None in key or key not in group_lookup:
-            pretty_key=', '.join([str(k)+'='+str(v) for k,v in zip(groupby, key) if v is not None])
+            pretty_key=', '.join([unicode(k)+u'='+unicode(v) for k,v in zip(groupby, key) if v is not None])
             pd = PlotData(pretty_key)
             pd.series = [ts]
             plot_groups.append(pd)
@@ -242,7 +243,7 @@ def plot_plots(plot_groups, save=None):
         uniq_units = list(set([s.units() for s in group.series]))
         uniq_units.sort()
         if len(uniq_units)>2:
-            logger.warning('more than two different units on the same plot')
+            logging.warning('more than two different units on the same plot')
             uniq_units = uniq_units[:2]
 
         # store each series in a slot corresponding to one of the units,