[EFL][WK2] Add setting to toggle developer extensions

[EFL][WK2] Add setting to toggle developer extensions
https://bugs.webkit.org/show_bug.cgi?id=96974

Patch by Seokju Kwon <seokju.kwon@samsung.com> on 2012-09-23
Reviewed by Kenneth Rohde Christiansen.

This is required to allow the user to inspect pages. (Web inspector)

* UIProcess/API/efl/ewk_settings.cpp:
(ewk_settings_developer_extras_enabled_set):
(ewk_settings_developer_extras_enabled_get):
* UIProcess/API/efl/ewk_settings.h:
* UIProcess/API/efl/tests/test_ewk2_settings.cpp:
(TEST_F):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@129327 268f45cc-cd09-0410-ab3c-d52691b4dbfc