solarized_dark: improve 256 color approximation

Solarized colors for 256 color palettes are not as closely approximated
as they could be.

256_base0 is set to g66 in Urwid's 256 color palette.  This corresponds
to #a8a8a8 in Xterm.  base0 should ideally be #808080.  This matches g50
exactly, so switch to that grayscale value.

256_base1 is set to g70 in Urwid's 256 color palette.  This corresponds
to #b2b2b2 in Xterm.  base1 should ideally be #8a8a8a.  We can't get
this exactly with Urwid's 256 color palette, but #848484 is a closer
approximation.  Switch to g52 to get this grayscale value.

256_cyan is set to #088 in Urwid's 256 color palette.  This corresponds
to #008787 in Xterm.  cyan should ideally be #00afaf.  This matches #0aa
exactly, so switch to that value.

Signed-off-by: Michael Turquette <mturquette@deferred.io>
adjusted unread-threadline theming
Merge branch '0.3.3-solarized-theme-fix-550'
Ignore EINTR in workers when terminating due to SIGTERM

If the child process is killed using SIGTERM by the parent, send(2)
can fail with EINTR. Install a signal handler for SIGTERM and ignore
EINTR in this particular case.

Fixes #325.

Signed-off-by: Justus Winter <4winter@informatik.uni-hamburg.de>
Merge branch '0.3.3-fix-325'
empty input queue as soon as

.. the current value cannot be prefix of any bound
keysequence. fixes #547
Merge branch 'master' of github.com:pazz/alot
fix 544

only sort messages with not-None date header,
append the rest
deliver an empty ListBox[] on error
Merge branch '0.3.3-fix-544'
Merge branch 'master' of github.com:pazz/alot
Merge branch '0.3.3-fix-nowait-547'
don't mention that first run creates default config

because it doesn't any more..
close #552
Merge branch '0.3.3-fix-docs-552'
Join worker processes and keep track of them in the log

This also prevents a zombie from hanging around until the next worker
is spawned by multiprocessing.

Fixes 411.

Signed-off-by: Justus Winter <4winter@informatik.uni-hamburg.de>
Merge branch '0.3.3-fix-411'
Replace workers std{out,err} by pipes and log anything written to them

This will help us identify problems in libnotmuch and reduces visual
artifacts (unfortunately libnotmuch writes messages to stderr that
used to clobber the curses interface).

Signed-off-by: Justus Winter <4winter@informatik.uni-hamburg.de>
Add some comments to the db manager async code

Signed-off-by: Justus Winter <4winter@informatik.uni-hamburg.de>
Merge branch '0.3.3-workers-love-555'
make sure urwid keeps track of updated TERM size

... after external processes terminate.

fixes #566