emulation: Fix escape sequences of keypad Home and End (take 2)

https://bugzilla.gnome.org/show_bug.cgi?id=600659#c63
vteapp: Add comment pointing to the bug
build: Dist box_drawing_generate.sh

https://bugzilla.gnome.org/show_bug.cgi?id=730140
build: Don't dist generated files
widget: doc: Clarify a comment about rewrapping