Better Cubiio Inkscape Stuff

This is regarding Cubiio, the 800mW laser engraver I got off Kickstarter

I made a slightly better Cubiio template and a slightly better version of the "J Tech Photonics Laser Tool" plugin.

Changes (Jan 26, 2018):

Renamed menu item to "J Tech Photonics Laser Tool (Cubiio)" for easy identification, works even if original plugin is still installed
All settings defaulted to the ones in Cubiio's instructions
Speed and power settings limited to Cubiio's maximum limits
Output directory set to "C:\CUBIIO" as default, makes it easier to save to SD card
Output file name extension changed to ".txt" by default
Warning dialog if file name is too long or missing ".txt"
Error dialog if unrecognized objects are found in the file (such as ellipses, text, rectangles)
Error dialog if Gcode goes out of the 100mm x 100mm area (this will cause Cubiio to crash if it ran the code)
Got rid of the "Gcodetools orientation point", so you don't have to worry about moving/deleting it accidentally
Inkscape opens without forcing the window to be very small
Gcode preview lines are thinner, the arrows are smaller
Directory is created if it does not already exist