[mdTable] indeterminate checkbox state, darker separator

[zcyzcy88]

Now, the top checkbox and separator when partial row select:

Expect like this:

(http://david-mulder.github.io/paper-datatable/components/paper-datatable/demo/paper-datatable-card/full-implementation.html)

[marcosmoura]

This will be done!

[ndevadas]

When I bind length of a data array to md-table-pagination like this v-bind:md-total="+products.length", both previosPage and nextPage buttons get dissabled.

[pablohpsilva]

@ndevadas could you please open a separate issue?
That will help us to fix this bug asap.