Add command to select all next occurrences for all cursors

Consider the following: <img width="160" alt="screen shot 2018-02-06 at 8 23 26 am" src="https://user-images.githubusercontent.com/2193314/35870688-207a2aa2-0b17-11e8-92f7-1cde31a3eeef.png"> Pressing cmd+d adds the quote to the right of `"Meta`: <img width="181" alt="screen shot 2018-02-06 at 8 24 49 am" src="https://user-images.githubusercontent.com/2193314/35870729-3af10752-0b17-11e8-81c0-2ff658d3e3d9.png"> Pressing it again does nothing, presumably because it saw that the next quote was already selected. This was the first time I did this, but I expected cmd+d to select the next item of each of the selections.