[MdSelect] options in disabled groups are selectable

[VdustR]

Steps to reproduce

Check the official documentation, and scroll down to "Disabled" example area. Select the disabled groups.

Which browser?

vue-material@1.0.0-beta-7

What is expected?

Those options in disabled groups should be un-selectable.

What is actually happening?

You can select the options in the disabled group.

Reproduction Link

official documentation

[hiddenwaffle]

I am still very new to this codebase, but I suspect that if this line were changed from checking "this.disabled" to "this.isDisabled" it would give the correct behavior:

vue-material/src/components/MdField/MdSelect/MdOption.vue

Line 80 in 9f61c0b

if (!this.disabled) {

My reasoning is that isDisabled() accounts for the injected "MdOptgroup" property, which appears to allow the component to inherit whether or not it is disabled based on the parent component.

[VdustR]

@hiddenwaffle thanks, that helps!