fix enyo.merge to work as intended

Enyo-DCO-1.1-Signed-off-by: Cole Davis <cole.davis@lge.com>
add feature of includeKeys to enyo.Model, change filterData to allow directional mutation of data payloads, fix construction/initialization to properly use and store attributes, add unit tests for features

Enyo-DCO-1.1-Signed-off-by: Cole Davis <cole.davis@lge.com>
Merge branch 'master' of github.com:enyojs/enyo into core
add ModelSupport mixin, convert Control to use mixin as well as ModelController and simplify ModelController

Enyo-DCO-1.1-Signed-off-by: Cole Davis <cole.davis@lge.com>