Most CJK users use IME (input method) to type CJK characters. They need
the cursor to be at the correct location, not in the bottom right
corner.
This CL does:
* Move the cursor the focus() element.
* Hide the cursor (and show it at exit)
* Intercept SIGINT to guarantee proper cleanup all the time.
This should fix the second issue mentionned on:
https://github.com/ArthurSonzogni/FTXUI/issues/2
