Use a deque instead of a list to store hilighted lines

This might speed up Pronterface while printing.
Indeed, as we keep adding items we keep expanding the list and Python has to
move it all the time.

printrun/gviz.py

@@ -12,7 +12,9 @@
 #
 # You should have received a copy of the GNU General Public License
 # along with Printrun.  If not, see <http://www.gnu.org/licenses/>.
+
 import wx, time
+from collections import deque
 from printrun import gcoder
 
 from printrun_utils import imagefile
@@ -151,8 +153,8 @@ class gviz(wx.Panel):
         self.fades = [wx.Pen(wx.Colour(250-0.6**i*100, 250-0.6**i*100, 200-0.4**i*50), penwidth) for i in xrange(6)]
         self.penslist = [self.mainpen, self.travelpen, self.hlpen]+self.fades
         self.showall = 0
-        self.hilight = []
-        self.hilightarcs = []
+        self.hilight = deque()
+        self.hilightarcs = deque()
         self.dirty = 1
         self.blitmap = wx.EmptyBitmap(self.GetClientSize()[0], self.GetClientSize()[1],-1)
 
@@ -168,8 +170,8 @@ class gviz(wx.Panel):
         self.arcs = {}
         self.arcpens = {}
         self.layers = []
-        self.hilight = []
-        self.hilightarcs = []
+        self.hilight.clear()
+        self.hilightarcs.clear()
         self.layerindex = 0
         self.showall = 0
         self.dirty = 1

pronterface.py

@@ -251,7 +251,8 @@ class PronterWindow(MainWindow, pronsole.pronsole):
                     layer = float(line.split("Z")[1].split()[0].split("*")[0])
                     if layer != self.curlayer:
                         self.curlayer = layer
-                        self.gviz.hilight = []
+                        self.gviz.hilight.clear()
+                        self.gviz.hilightarcs.clear()
                         threading.Thread(target = wx.CallAfter, args = (self.gviz.setlayer, layer)).start()
                 except:
                     pass