[Android] Support multiple icons for packaging tool.

This patch is to implement the feature about multiple icons for
packaging tool.
The icon size in manifest.json was defined by web developer, we
won't be able to predict the size, so we use interval to estimate
the icon size.

BUG=https://crosswalk-project.org/jira/browse/XWALK-690
Enable the use of the viewport meta tag

SSIA. Add '--enable-viewport-meta' command line argument
by default.
Merge pull request #1753 from pozdnyakov/Viewport_meta

Enable the use of the viewport meta tag
Fix Mac build.

- Result of comparison against a string literal is unspecified (use strncmp instead).
- Explicit destructors.
- Invalid conversion NULL -> bool.
Merge pull request #1758 from darktears/mac-build

Fix Mac build.
Bump version to 6.34.110.0
Bump version to 6.34.111.0
Merge pull request #1601 from wuhengzhi/multi_icon

[Android] Support multiple icons for packaging tool.
[Android] Launch Screen full spec implementation

As the spec defined, the launch screen contains 3 layers:
1. background color
2. background image
3. foreground image
It's impossible to show all these layers together when an icon is tapped, because
of the limitation of 'Android drawable'. The actual flow is as below:
display the first 2 background layers, and then display the 3rd foreground image layer.

Below is the description for the implementation in general:
Build script:
1. Parse manifest.json and customize launch screen
2. Generate drawable:launchscreen_bg.xml as the configuration defined.
3. Copy background and foreground images to res folders as expected.
Runtime:
1. Create a new layout to display 9-piece format foreground image.
2. Parse image-border from manifest.json, and customize the layout.

TODO:
One feature missed in this patch:
'ready_when' = 'user-interactive'

Spec=https://docs.google.com/a/intel.com/document/d/17PuNuHRTQuREUpaCvj-eEx7uYi2avd-VW-oaMXMpvwo/edit?pli=1#
BUG=XWALK-1198
[Android] Launch Screen test

Python testcase for Launch Screen feature.

BUG=XWALK-1198