Optimized memory alignment
Optimized memory alignment

Summary:
It's not much, but still 4 bytes saved here by moving the ```bool```s together. (on compilers where ```bool``` is a single byte)
Closes https://github.com/facebook/yoga/pull/319

Reviewed By: gkassabli, passy

Differential Revision: D4383686

Pulled By: emilsjolander

fbshipit-source-id: 9a48eccbb69382850c016aa6ee730526704a15f2

yihuang/css-layout,yihuang/css-layout,rmarinho/yoga,rmarinho/yoga,rmarinho/yoga,facebook/css-layout,facebook/yoga,facebook/css-layout,facebook/yoga,rmarinho/yoga,facebook/yoga,facebook/css-layout,yihuang/css-layout,yihuang/css-layout,facebook/yoga,yihuang/css-layout,rmarinho/yoga,rmarinho/yoga,yihuang/css-layout,facebook/css-layout,rmarinho/yoga,yihuang/css-layout,rmarinho/yoga,facebook/yoga,facebook/css-layout,facebook/yoga,facebook/yoga,facebook/yoga,facebook/css-layout,facebook/css-layout,yihuang/css-layout,facebook/css-layout,facebook/yoga,yihuang/css-layout,yihuang/css-layout,rmarinho/yoga,facebook/yoga,facebook/css-layout,rmarinho/yoga