[Android] Make prepare_r_java.py an executable

IDEs like eclipse are unable to run the program as an external builder
if they are not marked executable.

Also, use copy2 instead of copyfile to preserve 'x' bit in file mode.
[Android] Add eclipse build support for xwalk_core_library

Eclipse is a popular IDE for android development. So it's useful
to have this supported out of the box.

This change adds the .project, .classpath files required by Eclipse
for importing.
[Android] Refactor the python script to prepare xwalk core library

Use list of files/directories to avoid duplicated code for copying.
[Android] Add the test case about onPause and onResume.

This patch contains the test case about onPause and onResume on
embedded and shared mode. It's for the runtime client.
Invoke onPause or onResume on main thread, wait for some seconds
to ensure that we get the title. Then wait for two hundred
milliseconds, get the title again. Compare the two titles.

For embedded client test:
1. install XWalkRuntimeClientEmbeddedShell.apk
2. python build/android/test_runner.py instrumentation \
--test-apk=XWalkRuntimeClientEmbeddedTest -v -f testPauseResume

For shared client test:
1. install XWalkRuntimeLib.apk
2. install XWalkRuntimeClientShell.apk
3. python build/android/test_runner.py instrumentation \
--test-apk=XWalkRuntimeClientTest -v -f testPauseResume
[Tizen][Runtime Model] Fix installer crash if icon is missing from manifest.

Installation crashes if the icon field is missing from manifest.json.
However, this behavior is not correct.

The installation should not crash even though no icon is provideded.

BUG=https://crosswalk-project.org/jira/browse/XWALK-110
Merge pull request #1055 from wang16/refactor_prepare_core_py

[Android] Refactor the python script to prepare xwalk core library
Merge pull request #992 from gramakri-intel/master

[Android] Eclipse build support for xwalk_core_library
Merge pull request #1062 from shaochangbin/issues

[Tizen][Runtime Model] Fix installer crash if icon is missing from manifest.
Bump version to 2.31.30.0
Merge pull request #962 from wuhengzhi/pauseResume

[Android] Add the test case about onPause and onResume.
Refactor extension system
All test are passed