Adds const to more getters

adds `const` to more getters.
Merge pull request #3092 from ricardoquesada/more_const_love

issue #2373: Adds const to more getters
Merge branch 'iss2129-remove_prefix' of https://github.com/minggo/cocos2d-x into minggo-iss2129-remove_prefix
issue #2129: Bug fix in "Color4B::Color4B(const Color4F &color4F)".
vertex --> getVertex, originalVertex --> getOriginVertex.
iss2129: bug fix in CCDrawNode.cpp
issue #2129: Adding explicit for 'Color4B(const Color4F &color4F);' and 'explicit Color4F(const Color3B &color3B)'.
issue #2129: Using 'const FontDefinition&' instead of 'FontDefinition*' and resolving memory leak in FontDefinition LabelTTF::getTextDefinition()
issue #2129: FontDefinition* --> const FontDefinition&
issue #2129: Adding 'FontDefinition_to_jsval' and reverting some changes.
issue #2129: Reverting changes in cocos2d_specifics.cpp
issue #2129: Updating cocos2dx.ini.
issue #2129: Updating bindings-generator.
Adding some logs in travis script.
Merge pull request #11 from dumganhar/minggo-iss2129-remove_prefix

Bug fixes. Please see the commits for details.