Initial commit

- Generic class for digital multimeter.
- Generic interface for RS232 based multimeters.
- Implementation of UT-60E reader.
- Some generic-used triggers are implemented.
  For sure further improvement is needed.
Major project layout reshuffle

- Reshuffle files in the project.
- Added basic copyrights and copying information.
- Using CMake build system instead of old-fashion
  hand-written crappy MakeFile.
- Also includes some fixes for the DMM logic and
  communication.
Implement basic user interface

Supports digital display and graph display.

Graph scale and triggers are hardcoded at this moment.

Still loads of stuff to do here, but it's not a bad
starting point.
Add .gitignore
Replace own graph display with QCustomPlot widget

This widget brings all the functionality we need and
it's easier to re-use existing code. Would also mean
we're to switch to GPLv2+ for the final package but
that's not so bad.

Also corrected a bad logic when connection to DMM
failed.
Add GNU makefile to the root project folder

This way it's possible to type `make` from the
root project folder in order to compile all the
applications.
Add the README file and prepare going public
Add license files for the third party code