Moved what could be from inc to src.
Changed init order to keep like with like.

In the actual solution, terminfo and termios are separated. The goal
is to keep as much terminfo-specific init/fini and as much termios-
specific init/fini as contiguous as possible to prevent context
cycling between the two libs.
Sandbox now deletes cur_term on exit.
First pass at db and bindings for terminfo, termios.
Moved stream, file_stream from inc to src.
Updated forwards.
Binding now owns decoder and button id map.
Term_db now populates button id map when populating trie.
First pass at building decoder chain for terminfo|termios.
I18N in modifier-io.cpp.
Context push.

Started mucking about with seq mappings. The fact that the trie works
on hard-coded citer_t has finally become too much. It's going back
to using function templates.
Trie's lookup and insert methods are now templates.
Trie's methods now template on iter.
Bashed terminfo.hpp.

This was originally to safely undefine the nonsense that ncurses defines
in headers. It turns out, we need some of these and have to be more
careful about how we undefine it.
Added i18n to button enum names.
Updated binding for removed terminfo.hpp.
First pass at terminfo trie decoder.