Issue 1338: Increment CSS values at least significant digit

Steps to reproduce

  1. Inspect the blue <div> above
  2. Switch to the Style side panel
  3. Click on the value of the width property to start inline editing
  4. Press Up
    8em is shown inside the inline editor
  5. Press Ctrl+Up
    8.1em is shown inside the inline editor
  6. Press Shift+Up
    18.1em is shown inside the inline editor
  7. Press Down
    17.1em is shown inside the inline editor
  8. Press Ctrl+Down
    17.0em is shown inside the inline editor
  9. Press Shift+Down
    7em is shown inside the inline editor
  10. Press PageDown
    -3em is shown inside the inline editor
  11. Press PageUp
    7em is shown inside the inline editor
  12. Press Shift+PageDown
    -93em is shown inside the inline editor
  13. Press Shift+PageUp
    7em is shown inside the inline editor

Expected Results