[travis-ci] Speed up android build.
Merge pull request #2870 from dumganhar/master

[travis-ci] Speed up android build. [master]
merge pull reqeust fixing for iOS7 and Xcode5 into master
LabelTTF vertical alignment fixed on OS X

vertical alignment was broken on OS X.
top and bottom were switched.
If user has enabled debugger support, call enableDebugger() to setup the debug context, start the debugger thread, etc.
enableDebugger() will be called inside ScriptingCore when JSB_ENABLE_DEBUGGER is #defined
#define JSB_ENABLE_DEBUGGER 1