'drush dl' should treat project names case-insensitively

[joachim-n]

URLs for projects on d.org are case-insensitive, so Drush should handle them the same way.

Eg: https://www.drupal.org/project/entity_reference_revisions, https://www.drupal.org/project/Entity_reference_revisions

[joachim-n]

Note also that currently, once you try to download a project with uppercase letters, and then try again in lowercase, Drush incorrectly reports it can't be found -- which suggests that in the dl command's cache, things are case-insensitive!

$ drush dl Entity_reference_revisions profile Entity_reference_revisions
No release history was found for the requested project (Entity_reference_revisions).                                                                   [error]
Could not download requested project(s).                                                                                                               [error]
$ drush dl entity_reference_revisions profile state_machine
No release history was found for the requested project (Entity_reference_revisions).                                                                   [error]
Could not download requested project(s).                                                                                                               [error]
$ drush cc drush
'drush' cache was cleared.                                                                                                                             [success]
$ drush dl entity_reference_revisions profile state_machine
Project entity_reference_revisions (8.x-1.3) downloaded to /Users/joachim/Sites/drupal-8-commerce//modules/entity_reference_revisions.                 [success]
Project profile (8.x-1.0-alpha7) downloaded to /Users/joachim/Sites/drupal-8-commerce//modules/profile.                                                [success]
Project state_machine (8.x-1.0-beta3) downloaded to /Users/joachim/Sites/drupal-8-commerce//modules/state_machine.                                     [success]

[hansfn]

+1

This is a serious problem for people who (by accident) use an upper case letter when downloading modules. The module is blocked for downloading until Drush's cache is cleared.

I guess this problem eventually will be fixed when downloads are handled by composer exclusively, but until then ...