[Windows] Fix runtime is using wrong content_app target

On Windows, upstream is trying to provide alternative to split
chrome.dll into several parts. Therefore, target content_app
is now content_app_browser, content_app_child, content_app_both.
It's not relevant with xwalk, xwalk should use content_app_both
to obtain all it need for content app.
Merge pull request #1003 from wang16/fix_windows

[Windows] Fix runtime is using wrong content_app target
[Android] Add getDisplay() to XWalkDisplayManager

WiDi PR #965 add XWalkDisplayManager class referenced from
DisplayManager class introduced since Android 4.2 (API Level 17).

While getDisplay() is not included because WiDi does not use it.
This PR is adding that this api and implementation.
[Android] Add XWalkManifestReader.java to xwalk_core_library project.

The Java class XWalkManifestReader provides the content of app
manifest. Missing of XWalkManifestReader will lead to error of
core library project, so add it to xwalk_core_library.

This patch also fixes some coding style issues.
[Android][Extensions] Implemented W3C SysApps Device Capabilities API

The implementation is based on 17 October 2013 editor draft version.
CPU, Memory, Storage and Display are included, the Audio and Video Codecs
is not implemented yet.

SPEC=http://www.w3.org/2012/sysapps/device-capabilities/
BUG=https://crosswalk-project.org/jira/browse/XWALK-48
[Android] Destroy extension when activity is destroyed

This fix is to ensure that XWalkExtension object gets destroyed when the
Activity is destroyed (e.g. press back button).

Since each XWalkExtension object on Java side has a corresponding native
extension object, we need to make sure the native extension object is
also destroyed. Otherwise, the leaked native object will cause unpredictable
program behavior.

BUG=https://github.com/crosswalk-project/crosswalk/issues/1023
Merge pull request #1042 from gaochun/cordova_xwalk

[Android] Add XWalkManifestReader.java to xwalk_core_library project.
Merge pull request #961 from halton/device_capabilities

[Android][Extensions] Implemented W3C SysApps Device Capabilities API
Merge pull request #1030 from hmin/destroy-extension

[Android] Destroy extension when activity is destroyed
[Android] Use loadAppFromManifest if a manifest.json is used for a web app.

Add loadAppFromManifest support for web app. If web app is packaged with
manifest, directly use loadAppFromManifest API to load app.
Because native manifest parser only supports original proposal
"app:launch:local_path", manifest related test cases are modified.
When the specfication for manifest is stable, will revisit these test
cases and native manifest parser.

BUG=https://crosswalk-project.org/jira/browse/XWALK-100?filter=10007