Complete rewrite of time estimation with acceleration

Fixed documentation regarding wxPython on MacOS Lion

changed instruction for MacOs Lion to download stable wxPython because unstable version breaks the axis control panel

Faster firmware startup for sanguinololu and similar boards

Fix manually input port names

port setting is now also respected if the port exists but is not detected in scan (for udev symlinks)

  Accounts for G4 Pxxx
  Accounts for Z moves as well.
  Also prints out duration for each layer while calculating the total time.

  Does not use individual axis acceleration, only uses sprinter default acceleration 1500.0 mm/s/s
  Does not count E for timing... so if E is slowing down the move, we're not accounting for that.

** fixed: 2x distance to reach full speed, because accel and decel to 0.0 at each move.

TODO:
  Get Device Caps (per axis acceleration, per axis speed limits)
  anything else...?

Sends M21 whenever SD Upload or SD Print are used.

Automatically attempts to initialise the SD card whenever either of the SD
card related buttons are used.

Added Current Z-Height to the status message.

Also added "Print Began at: HH:MM:SS"
and added the message "Print Ended at: HH:MM:SS: and took...

Improved status line estimated time remaining.

Fixed the time estimator in pronsole.py

at beginning of move set feedrate to average of last and current feedrate.  do move with that feedrate.
then set the feedrate to the current feedrate.
if it's just a feedrate change, then the feedrate will become the feedrate.
if there is no feedrate in current move, feedrate will be last feedrate
if there is a move and a new feedrate then the move will take however long the average feedrate would take.

estimation is a bit more optimistic than pessimistic.  however it seems to be a lot more accurate.

uses format:
SD Printing: pp.p% | Est: hh:mm:ss of hh:mm:ss of hh:mm:ss remaining
Printing: pp.p% | @ Line# xxx of yyyyy lines | Est: hh:mm:ss of hh:mm:ss remaining

Added an Estimated Time Remaining of Total Time to the status bar.

for non-SD Printing. They get more and more accurate until the end.

Catch exception so that disconnection does not give a traceback

Small change to enable T0 and T1 commands.

French translations update

Experimental