New Prop: selectFirst

[RohitRox]

If true, selects first option by default

I could have created a pull-request to master, the code is good to go to master, but we need this in 1.1.9 or 1.x branch, so ended up creating pull request to 1.x or I can create a request to master and you can apply that feature to 1.x Any better ideas?!