shell: Fix shell command output

Shell command output was broken in @8a5a8db, which refactored nvim to no longer
switch to cooked mode(linefeeds are processed differently).

Fix the problem by refactoring write_output to accept to extra arguments that
control the flushing behavior and where data will be written to: buffer or
directly to the screen.
deps: Fix 32-bit build of lib{unibilium,termkey,tickit}
Merge PR #1613 'Fix shell command output'
Revert "deps: Fix 32-bit build of lib{unibilium,termkey,tickit}"

This reverts commit f76df2475356add68212d737acd7da5bba3b64d6.
deps: Fix unibilium/libtickit URLs
Merge PR #1620 'Fix 32bit unibilium build'
Allow building as a static library
Add library to build scripts