[Tizen] Move platform sensor initialization out from browser UI thread.

Cold start time of sample Calulator application increases to ~1080 ms on
Tizen VTC-1010 at the moment. One bottleneck is it takes long period to
initalize platform sensors inside browser main thread, which blocks native
window display and starting render message loop.

The CL moves the platform sensors initialization outside of browser main
thread. The local test result shows it shortens ~200ms of cold start
time.

BUG=XWALK-2520
[Android] Replace external extensions with source instead of jar

The prebuild jar files of external extensions may out of date as
the runtime is walking forward. So place them with source code.

BUG=https://crosswalk-project.org/jira/browse/XWALK-2539
Merge pull request #2460 from shaochangbin/sensor-launch-time

[Tizen] Move platform sensor initialization out from browser UI thread.
[Tizen] Fix secure-storage dependency

BUG=XWALK-2707
Merge pull request #2469 from DonnaWuDongxia/replaces-jars-gypi

[Android] Replace external extensions with source instead of jar
[Tizen] Moved Tizen specific code related to WebSetting extension between #if defined(OS_TIZEN) #endif

BUG=XWALK-2726
Merge pull request #2500 from jizydorczyk/fix-encryption-dependency

[Tizen] Fix secure-storage dependency
[Android] Increase the open files limit

As Crosswalk uses in-process mode, that's easier than Chromium
to reach the default limit(1024) of open files per process on
Android. So increase the limit to 4096 explicitly.

BUG=XWALK-2655
Merge pull request #2499 from xingnan/increase-open-files-limit

[Android] Increase the open files limit
Bump version to 10.38.224.0
Merge pull request #2501 from jizydorczyk/websetting-defines

[Tizen] Moved Tizen specific code related to WebSetting extension
Split xwalkctl and pkgcmd backend

All the application management (app un/installation) logic is now removed
from it 'xwalkctl'- it is only responsible for XWalk common settings,
like setting of debugging port.

The application management is moved to a separate target: xwalk_backend.
The wrapping script is removed as well.

BUG=XWALK-2671
BUG=XWALK-2579