linux speech synthesis: switch to eSpeak

Conflicts:
	QGCExternalLibs.pri
	src/GAudioOutput.cc
Added 2 kPA offset to pressure measurements to get HIL closer to real conditions
Fixed wrong location of offset constant
flightgear: add configurable barometer offset
Merge remote-tracking branch 'upstream/master' into espeak

Conflicts:
	QGCExternalLibs.pri
	src/GAudioOutput.cc
	src/GAudioOutput.h
remove alsa asound library dependency comment
fix merge errors and unused-variable error
Changes to allow msbuild to build installers

No idea why, but manipulating CONFIG inside the build file confuses
msbuild command line builds. Work fine if you build from the IDE!
QGCMessageView: Extensive code cleanup and bug fixing.
Right-click menu works cleaner.
Coloring of output text is correct.
Output text now handles all severities of messages.
QGCMessageView: Added timestamps.
Message view: Forgot to remove debugging output.
Google earth: Corrected #ifdef for Google Earth-specific code.
Merge branch 'master' of github.com:mavlink/qgroundcontrol into message_view
Simplified formatting
message view improvements
Fix unneeded QObject::connect which was failing

The connect call was generating debug output to identify that it was
failing. After looking at the code realized that this connect is not
needed. The group box is removed when UASListWidget::removeUAS method
is called.

Second change in the file fixes a crashing bug when the last UAS is
removed. Need to exit the iterator after we modify it.
Fix crash after last UAS is removed

ui->waitingLabel is deleted and set to NULL when mode is PX4. Must
check for NULL before using it.
Merge pull request #564 from DonLakeFlyer/ConnectFix

Failed QObject::Connect fix
Fix failed connect

There is no such things as a clicked signal on QWidget. You activate
new UAS from right-click menu.
Fix failed connect

showLabel was connected to signal but not set as a slot