We need to use Result<> to manage error flow,
at least on the methods API. This way it will
finally feel idiomatic Rust and more concise.
Also, we can't return a non Result from main.
- rename NcResult to NcIntResult.
- new NcError & NcResult types.
- new error![] macro to reduce boilerplate.
- change return type of NcDirect methods to NcResult.
- refactor several examples to return NcResult:
direct-cursor, poc-direct & poc-kittyzapper.
- BONUS: fix test not stopping notcurses context.
- update lib doc-comment.
- fix typo in readme.
- fix notcurses_init unit test
- fix fn call name: `nplane_at_cursor_cell` → `ncplane_at_cursor_cell`.
- make LIBC_FILE & NC_FILE type aliases with doc comment.
- add lib module comment.
- improve direct-cursor example.
- fix full-text example and rename it to full-basics.
- remove _IO_FILE import and usage.
- create handy constructors for NcDirect & Notcurses.
(but can't implement destructors for copy types…).
- when possible substitute mutable pointers `*mut` for mutable references `&mut`
with associated lifetimes.
- new widgets module, starting with NcReader & NcReaderOptions constructors
