cellcounter/cellcounter#236

Fix for cellcounter/cellcounter#236

1. Implementation of new modal dialog for selecting keymaps saved by the user
2. Changed behaviour of edit keymap dialog
    1. Close now closes without saving, or reverting the keyboard - in line with user intention
    2. Revert (previously cancel) now always reverts - again in line with clear user intention
3. Removed commented code from the top of ```count.html``` template.