android.mk: Simplified NATIVE_HEADERS dependencies
android.mk: Pass cache setting to submakes
NEWS: prepare for 6.6.1
Makefile: link harness.a with src/Audio/VegaVoiceSettings.cpp

Fixes linker failures.
po: update Polish translation
po: update German translation
po: update xcsoar.pot
DeviceListDialog: indicate duplicate devices in list

Label them "duplicate" instead of "error".
device: compare port type first in DeviceConfigOverlaps()

Simplifies the function by reducing duplicate code.  The PortType::PTY
case was broken because the type comparison was hard-coded to
PortType::SERIAL.
device: allow using more than one TCP/UDP device

Compare the configured port in DeviceConfigOverlaps().  Now two TCP
devices don't overlap if the port is different.
DeviceDescriptor: eliminate obsolete NMEAOut kludge

This kludge has been obsoleted by the move to FileEventHandler last
year (commit 6f05ae6e).
DeviceDescriptor: rename Open() to OpenOnPort()

Reduce confusion wit the other Open() overload.  One is internal, one
is external.
DeviceDescriptor: check cancellation state in OpenOnPort()

Abort the whole operation if the user has pressed "cancel".
DeviceDescriptor: count the number of open failures

Prepare for next commit.
DeviceDescriptor: work around Android/BT crash bug

See code comment.
Screen/Files: add ROSA Linux font paths
Manual: Some more checks on the supported dev table.
Profile/Profile: Consider empty ("") paths as not set

Regression introduced in commit e2c5daee54b58640e8fcc53f5314722c75ae1cc5

Fixes trac issue #2803.
po: update Greek translation
po: update German translation