changed criticalMessageBoxOnMainThread(const QString& title, const QString& msg) to QGCMessageBox::warning

I understand the intent when this was first created but nobody is using it and it no longer fits the context. If and when a need to abstract the serial link comes back, we can revisit this.

Removed "Clear Text" context menu from roll down dialog
Fixed "Clear Text" context menu in Info Dialog (renamed to "Clear Messages" in the process)

Also converted qDebug statements to logging category

Shrunk the Message drop down dialog a bit.
Made the Message drop down dialog slightly transparent.

Replace QMessageBox::warning by QGCApplication::criticalMessageBoxOnMainThread and removed unnecessary copying action

Added to ". Please provide a different file name to save to." to the error dialog

changed QGCApplication::saveTempFlightDataLogOnMainThread(QString tempLogfile) to enable overwriting files
existing file is removed before saving file (QFile::copy cannot overwrite files)

problem:
in src/ui$/HUD.cc copyImage(UASInterface* u): u->getImage() was called twice. The first called already erased the buffer.

changes:
src/ui/HUD.cc: copyImage(UASInterface* u): instead of getting the image a second time, we take the one we already fetched

I noticed that some times, the disconnect signal would get to the updateConnect button (tool bar) before the link was physically disconnected. That would cause it to count it as a still connected link and get the connect button logic out of sync.
While at it, added an interface to the UDP link to return its configuration instance. That allows the LinkManager to unlink it when disconnecting it.

This came through google groups and as the change is right where I'd been working, I added it here to avoid collision.

The goal of this first installment is to organize the code a bit so it's more readable,
clean up a bit of left over cruft, and manage link configurations (and links in general).

- Much simpler UI
- MVC style qml programming model

Put back commented out code

- Updated MainWindowTest to catch this problem
- Also implemented initial pass at SetupView unit test

- Updated MainWindowTest to catch this problem
- Also implemented initial pass at SetupView unit test

Include support for both param sets

The parameters for calibration were changed in the latest master. QGC
needs to work with both. Hacked in for now, waiting on a true parameter
re-mapping implementation.

There's also a partial fix for the databits and stopbits. I'm unsure how to deal with the logic
around the 'is_cdc' variable, as I can't really follow what it's for.

Controls respect QGCPalette settings. Also added test window.

Since this is generic Qml support not specific to FactSystem