Based on my testing, these seem to prefer not having a backslash on the end.
Merge pull request #299 from greggles/patch-1

Remove backslash from site alias drush-dir docs.
Fix #293. Change argument handling in user commands to use _csv_to_array() helper function.
Remove superfluous command callback specifications in user.drush.inc.
Enable cache while making the core projects in-place.

Contrib projects are made in a subprocess using the `make-process`
backend command, and they get the `'cache'` parameter set properly.
This is not the case of core, which is built separately.

This means that, in particular, any specified core patch will
not be cached.
Use correct hook name in docs - hook_drush_sql_sync_sanitize().
Replaced config-view strings by config-get
Fix #310. Reduce the minimum PHP to 5.3.0 from 5.3.3.
Convert the $expire argument to a valid value. Handle cases were $data is an object, or neither an object or array.
remove commented out code.
Provides a better user experience when `cc all` called outside Drupal directory.

This is to stop the issue of calling Drush cache clear outside a Drupal directory and not realising it.   

For instance a Drupal site is located in /var/www/oursite/html/ and you navigate into /var/www/oursite/ and call drush cc all.   

Currently calling `drush cc all` in a non Drupal directory  

'drush' cache was cleared.          [success]   

Is pretty easy to confuse with calling `drush cc all` in a Drupal directory. (Even though they have slightly different messages they both return success)

'all' cache was cleared in /var/www/mch/mch/htdocs#mch  [success]   

  
I have modifed the command to return 

No Drupal site found, only 'drush' cache was cleared.  [warning]
Only warn if you pass in type all and it is changed to drush

As per suggestion from @greg-1-anderson
Added back $type == FALSE use case.
Merge pull request #317 from p4ul/master

Provides a better user experience when `cc all` called outside Drupal dir
Simplify warning message code in instance when only 'drush' cache cleared
#1989174 Prevent makefile recursion through per-project properties
Merge pull request #320 from grasmash/1989174-do-recurse-property

#15 Prevent makefile recursion through per-project properties
Add some instructions on configuring sendmail.
#322: Automatically disable outgoing emails during Drush unit tests
Merge branch 'auto_sendmail_path' into sendmail_path