[xwalkdriver] Update xwalkdriver for android & tizen

 - update webdriver.cfg for deferent platforms
 - Pack WGT zip
[wrt]update testsprefix for manifest and packertool

[Detailed commit message (if have)]
Impacted TCs num(approved): New 0, update 0, deleted 0
Unit test platform: [tizen]
Unit test result summary:
tcs run block,BUGID:https://crosswalk-project.org/jira/browse/XWALK-1590
no tcs change, update README and execute path, pack and run the python script ok.
Merge pull request #871 from linshen/shenlin/wrt/optissue

[wrt]update testsprefix for manifest and packertool
Merge pull request #538 from yunxiaoxie/yunxiaoxie/webdriver

[xwalkdriver] Update xwalkdriver for android & tizen
[wrt] Remove unused common suites
Merge pull request #870 from kangxu/kangxu/wrt/wrtandroid/removeSuites

[wrt] Remove unused common suites
[usecase-wrt][XWALK-1668][XWALK-1649][XWALK-1731]Add 3 tcs for wrt-usecase-tizen-tests

[Detailed commit message (if have)]
Impacted TCs num(approved): New 1, update 1, deleted 0
Impacted TCs num(designed): New 2, update 0, deleted 0
Unit test platform: [tizen]
Unit test result summary: Pass 2, Fail 0, Blocked 0
Merge pull request #863 from linshen/shenlin/usecase/audio-multiuser-pkgmgr

[usecase-wrt][XWALK-1668][XWALK-1649][XWALK-1731]Add 3 tcs for wrt-useca...
[wrt] Update suite.json for testapp
Merge pull request #876 from kangxu/kangxu/wrt/testappfolder/add

[wrt] Update suite.json for testapp