cr2: make all imports relative

pylint rightfully complaints about it, so fix it before it becomes a
problem

Change-Id: Iaca7ebc2983d2b4d3871270665fb72558f6a9494
diff --git a/cr2/thermal.py b/cr2/thermal.py
index b183b71..f06fba9 100644
--- a/cr2/thermal.py
+++ b/cr2/thermal.py
@@ -22,9 +22,9 @@
 import re
 from matplotlib import pyplot as plt
 
-from base import Base
+from cr2.base import Base
 from cr2.run import Run
-from plot_utils import normalize_title, pre_plot_setup, post_plot_setup, plot_hist
+from cr2.plot_utils import normalize_title, pre_plot_setup, post_plot_setup, plot_hist
 
 class Thermal(Base):
     """Process the thermal framework data in a ftrace dump"""