[Feature Request] Additional icons added to Select All, Cut, Copy, & Paste

[jaypuk]

Is your feature request related to a problem? Please describe.
When using DumbPad to copy text/scripts it'd be very handy to transfer data to & from the clipboard via the mouse alone.

Describe the solution you'd like
A few more icons next to the existing ones - One each to Select All the text in the notebook, and to Cut, Copy, & Paste via the os's clipboard

Describe alternatives you've considered
The current alternative is to use the keyboard once you've selected the text within a notepad - Ctrl-A, Ctrl-C etc

Additional context
Add any other context or screenshots about the feature request here.