Encourage the practice of using the Drupal issue node id as patch array key.
Fix to make.project.inc to respect working-copy setting in download array
Allow contrib_destination to be managed per project.
Drush's own bootstrap is now called preflight and a new DrupalBoot class owns the rest of the bootstrap.
Add a missing file.
Move drush_command_belongs_to_disabled_module() to Drupal's command.inc
Move --early processing after preflight.
Rename Drush's kilobyte constant.
Remove a no-longer-needed return statement.
Add collection support to config-export
Add collection support to config-import
Add composer server installation instructions

Fixed #644 [ci skip]
Fixed typo
Fixed more typos
Reworded the "important" note per feedback
Removed local/global aspect from Install Composer task
Fix issue where Drush assumes multi-site on D8 when installing to a
symlinked docroot.
Prepare for alpha3
Back to dev.
Use Symfony Process for running commands.

Allows for capturing stderr, timeout for runtime and time without
output.

Ensures that the environment doesn't get polluted.

And a few minor fixes.