Initial commit. Functional version used for demonstration.

Signed-off-by: Andreas Kurth <akurth@student.ethz.ch>
Added headers to all files containing class descriptions, author information, original references and license text.
Code cleanup

Restructured code and removed obsolete methods and header files. Inserted some clarifying comments.
Renamed FrequencySpectrum::calcNumDisplayBars to calcNumFrequencies.
Improved error handling in BFConnectionThread and adjusted MainWindow to display errors

BFConnectionThread:
- initTTY and changeBaud return -1 when they encounter an error
- run checks their return values against -1
- run does not continue if one method fails
- die handles error messages and error numbers
- errorOccured signal carries an error message

MainWindow:
- handleConnectionError slot takes and displays an error message
Made MainWindow resizeable

- MainWindow adjusts content on resize
- SpectrographWidget handles resizeEvent
Made SettingsDialog vertically resizeable

SettingsDialog:
- now contains two GroupBoxes for additional settings
- adjusts content on resize and is no longer fixed size
- has its "Apply" button removed
Merge branch 'feature/resizeableWindows' into develop
Amplitude scale can be set in preferences
Expanded and reordered SettingsDialog

- renamed various labels
- added settings for baud rate (deactivated for now), USB device and hex file
Store settings in a file, handle new SettingsDialog inputs

MainWindow:
- read settings from SettingsDialog on startup

SettingsDialog:
- read settings from file (defaults set in UI elements initial values)
- write settings to file on change
- handle USBDeviceName and HexFileName
USBDeviceName and HexFileName can be configured in settings

MainWindow:
- read settings from SetDialog and initialize BFConThread with these values

BFConnectionThread:
- take USBDeviceName and HexFileName from constructor arguments instead of hard-coded values
Merge branch 'feature/improvedSettings' into develop
Fixed a warning from comparing signed/unsigned integers
Merge branch 'master' of https://github.com/accuminium/BF-FFT-Demo into develop