patman: Move to absolute imports

At present patman sets the python path on startup so that it can access
the libraries it needs. If we convert to use absolute imports this is not
necessary.

Move patman to use absolute imports. This requires changes in tools which
use the patman libraries (which is most of them).

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/buildman/builder.py b/tools/buildman/builder.py
index b7f2c42..f8e71de 100644
--- a/tools/buildman/builder.py
+++ b/tools/buildman/builder.py
@@ -19,10 +19,10 @@
 
 from buildman import builderthread
 from buildman import toolchain
-import command
-import gitutil
-import terminal
-from terminal import Print
+from patman import command
+from patman import gitutil
+from patman import terminal
+from patman.terminal import Print
 
 """
 Theory of Operation