[WIP] Refactoring and improvements

[iBelieve]

• Initial work on a QPM package
• Add a C++ plugin
• Implement Device and Units in C++
• Units uses the new HiDPI code from Qt 5.6, defaulting to new per-screen calculations on Qt 5.5 and earlier.
• Units.dp/Units.gu become properties instead of functions because C++ methods won't trigger binding updates like properties do
• Units.dp/Units.gu are exposed as dp/gu in all the top-level Window via UnitsHelper
• Icons/fonts are no longer all included. Icons are only included as necessary via the icons.yml file and icons.py script

TODO:

• Implement optional fonts
• Verify that the QPM package will work
• Fix failing unit tests

Fixes #384
Fixes #382
Fixes #380
Fixes #363
Fixes #359
Fixes #358
Fixes #394
Fixes #381

[marco-piccolino]

this is huge! looking forward to the merge

[IdrissDimson]

This seems like a really exciting update!

[nimaim]

Agree, this seems like one hell of an update! Thanks @ibeliever !

[alexkreidler]

Yay! It is merged!

[IdrissDimson]

\o/ Now to work on 0.2!

[luntik2012]

Thank you!
I don't know, where could I ask this, but what you guys think about QtLabControls? Will you merge with it? Did you seen it? Will you assist Qt-team with this somehow?