Refactoring started.
Aiming at a clean inner structure.
Bug fix.
I found right click on mirror copy had enbugged.
Localize vertex search
Not so effective...
paste bug fixed...
Easy mistake...
Fast paste
adding new lines is improved but still slow and more drawing is ...
State transition fixed
Correctly get back to previous state.
Bug fixed.
Undo of inputting a segment was broken...
Some texts are moved to "issues" tab.
Merge commit '2bdf0d82f326a40a4a2819f2f0f3be0dee28d94b'

Conflicts:
	README.md
merging
Merge remote-tracking branch 'origin/master'