You can clone with
HTTPS or Subversion.
1) Double click a word.
2) Press Shift-Left arrow.
Selection contracts on the right.
Selection expands to the left.
Note: The system behavior for double or triple clicked selection does not have a fixed anchor or head until the the keyboard biases it.
I'm not sure what other systems do, but this throws me off in CodeMirror.
This doesn't bother me very much, but a pull request would be welcome.