[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
Fix permissions in some test and source files.

Remove the executable bit that should have never been set in the first
place.
[Tizen] New discovery page for devtools.

Add chrome style decorates to discovery page of devtools to improve user experience.

BUG=https://crosswalk-project.org/jira/browse/XWALK-2525
[Tizen] No need to show crosswalk icon
The icon of crosswalk is shown on ivi-ux-ico which is not correct.
This fix modifies the crosswalk config file to not show its icon by default.

BUT=TC-1708
Merge pull request #2497 from yejingfu/bug-fix

[Tizen] No need to show crosswalk icon on ivi-ux-ico
[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The prebuild jar files of external extensions may out of date as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 #2409 from iKevinHan/new-devtools-page

[Tizen] New discovery page for devtools
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
Merge pull request #2502 from pozdnyakov/split_xwalkctl_and_pkg_backend

Split xwalkctl and pkgcmd backend
Merge pull request #2496 from rakuco/remove-executable-perms

Fix permissions in some test and source files.
Bump version to 10.38.225.0