We add log4rs create for logging across Zellij. Additionally, we capture
`stderr` output from plugins and log it the same log file as other
Zellij logs.
* refactor(fakes): clean up add_terminal_input
* refactor(fakes): append whole buf to output_buffer in FakeStdoutWriter::write
* refactor(fakes): append whole buf to output_buffer in FakeInputOutput::write_to_tty_stdin
* fix(fakes): allow partial reads in read_from_tty_stdout
This patch fixes two bugs in read_from_tty_stdout:
* if there was a partial read (ie. `bytes.read_position` is not 0 but
less than `bytes.content.len()`), subsequent calls to would fill `buf`
starting at index `bytes.read_position` instead of 0, leaving range
0..`bytes.read_position` untouched.
* if `buf` was smaller than `bytes.content.len()`, a panic would occur.
* refactor(channels): use crossbeam instead of mpsc
This patch replaces mpsc with crossbeam channels because crossbeam
supports selecting on multiple channels which will be necessary in a
subsequent patch.
* refactor(threadbus): allow multiple receivers in Bus
This patch changes Bus to use multiple receivers. Method `recv` returns
data from all of them. This will be used in a subsequent patch for
receiving from bounded and unbounded queues at the same time.
* refactor(channels): remove SenderType enum
This enum has only one variant, so the entire enum can be replaced with
the innards of said variant.
* refactor(channels): remove Send+Sync trait implementations
The implementation of these traits is not necessary, as
SenderWithContext is automatically Send and Sync for every T and
ErrorContext that's Send and Sync.
