Improved Shortcuts

[stefnotch]

In my opinion, the current shortcuts could be improved a little bit.

My suggestions are

• Delete to delete the current node. CTRL + X already cuts the current node, so being able to delete the node would make sense.
• CTRL + S during text editing to save the mindmap.

[Cedoor]

Hi @stefnotch,
there is already a shortcut the current node: ALT + -. While for the second point, it is necessary to fix the mmp library, I add the task!

Thank you.