Linux: added project part for QtCreator.

Allows easily setup cocos2d on Linux in QtCreator IDE.
Enabled c++0x flag, use OpenAL audio backend by default.
Add ProtocolUser for custom system plugins.
issue #2305:remove unneeded comment
Merge branch 'develop' into ForUser

Conflicts:
	plugin/protocols/platform/android/PluginFactory.cpp
	plugin/protocols/proj.android/jni/Android.mk
Merge branch 'develop' into ForUser
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-x into ccx_filesystem
issue #2317, Adjust ProtocolUser for actual situation.
issue #2317, Add plugin qh360 .
closed #2317, Add sample project HelloUser.
Merge branch 'develop' into ForUser
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-x into develop
Share top level Makefile between emscripten, linux and nacl.

Remove the custom top level Makefile.emscripten and instead
add build-emscripten.sh which can be used like build-linux.sh
and build-nacl.sh.

Also, use the top level lib folder to store emscripten libs.
This brings it in line with the other make-based builds.
Fix emscripten build on linux

Remove the dependacy of the emscripten build on /Library/Fonts
(a darwin-only folder).  On non-darwin platforms we use the
ariel.tff that is part of TestCpp.
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-x into develop
issue #2305: Using c++11 std::thread instead of pthread for HttpClient class.
issue #2305: Fixing a crash when error is triggered in WebSocket. Using std::lock_guard to replace lock and unlock manually.
issue #2305: Reverting to use lock and unlock for HttpClient.
issue #2305: Fixing a bug that passing wrong mutex parameter to "wait".
issue #2305: Using the old logic of "wait".