Merge pull request #9282 from twadleigh/release-0.3

Backport: Merge pull request #9251 from twadleigh/stdio-hack
use aws download on appveyor instead of status.julialang.org
run win64 tests in serial on appveyor

trade slower build times for hopefully better reliability

[ci skip]
(cherry picked from commit 4b4d8227b60734de417685bcf245043a9a3bfff2)
Fix typo in "R differences" subsection

Example Julia array has a typo and results in an error.
Merge pull request #9307 from sbromberger/patch-1

Fix typo in "R differences" subsection
fix #8551 and make stack switch more efficient

previously, each new stack would have a copy of a small portion of the
stack that started it. in small amounts, this was fine, but it is bad if
the user is starting many tasks. additionally, it wasted memory inside
every task to have a per-task base_ctx.

(cherry picked from commit ac1371136e1aae1ca7366b4d19cc0ffa0d659d72)
Draft of a slurping/splatting section FAQ answer

(cherry picked from commit 29d0a8e4e6d1fca92f812bc100d2d523ca2586eb)
Add mention of lexical scoping in Variables and Scoping

(cherry picked from commit 5c04ee955d6e52a6a4a438ed172ca65093f1c18b)
ref: #9267

edit explanation of lexical scope
(cherry picked from commit 2be0c80f466e82e4583530008291ee44238ebf79)
disable appveyor email notifications

[ci skip]
(cherry picked from commit 5a9b31ad1587270311491719b498c298aa748c53)
Fix #9317

(cherry picked from commit f140ff2443b9f1a92b32e93997e0f1325fccd2d8)
Added uv.h and dependencies to distribution.
Remove references to installing libuv.a