Fix for handling temperature G-code commands with float values

[asimonen]

What does this PR do and why is it necessary?

In my configuration, Cura is generating temperature setting G-code lines with float values like this:
M140 S50.0

Those work fine with Octoprint and Klipper, but seem to cause issues with SmartPreheat:

...
  File "X/lib/python2.7/site-packages/octoprint_smartpreheat/__init__.py", line 100, in get_temps_from_file
    temp = int(tempMatch.group("value"))
ValueError: invalid literal for int() with base 10: '50.000000'

Removing the fraction part from the G-code file fixes the issue, but I think SmartPreheat should also be able to handle them as well.

How was it tested? How can it be tested by the reviewer?

I've used it for several prints in my x86 Ubuntu/Python 2 based Octoprint+Klipper setup.
To test, modify a G-code file and add the fraction part to M104/M140/M109/M190 commands.

[kantlivelong]

Thanks. Will merge ...eventually...

[kantlivelong]

Merged into devel via 89a27b8. Cheers 🍺