Updated syncthing to v0.10.5.
Bumped version to 0.5.7.
Removed signing config from build.gradle.

The signing can be done in Android Studio now.
Fixed crash in FolderObserver if folder can't be accessed (fixes #180).
Updated dependencies.
Use correct announce server port for new installs.
Imported translations.
Bumped version to 0.5.8.
Fixed wrong devices being checked for a node (fixes #89).

Also, don't show the local device in device selection.
Allow opening folder in other app by long clicking (fixes #175).

Unfortunately, there is no folder mime type that seems to work
with popular file managers, so we use '*/*', which means the list
contains a lot of apps that don't make sense.
Added Travis CI support.