Handle EINTR in I/O loop
Handle EINTR in I/O loop

This fixes an issue where encountering some signals panicked the event
loop thread.

Resolves #76

dannydulai/alacritty,jwilm/alacritty,jwilm/alacritty,alacritty/alacritty,alacritty/alacritty,jwilm/alacritty,dannydulai/alacritty,jwilm/alacritty