Expand macros and quoted variables inside << >>, closes #1063
Revert "Expand macros and quoted variables inside << >>, closes #1063"

It broke the build. Reopens #1063.

This reverts commit 93f71c86242155fc026c2f814947e77621714432.
Add missing unquote/unquote_splicing documentation
Expand macros and quoted variables inside << >>, closes #1063
Ensure record args are evaluated in the parent context, closes #1065
Implement capture_io for ex_unit
Propagate dependencies in mix tasks

Closes #1036
Merge pull request #1068 from ericmj/mix-propagate-deps

Propagate dependencies in mix tasks
Merge pull request #1059 from mururu/io_protocol

Implement capture_io for ex_unit
Ensure no group_leader leakage on capture_io and remove stderr test which was printing on run
Remove unused variable
Also allow explicitly capturing of stdio and stderr