Documented the Change the Default Command in the Console component
Added the version number where the setDefaultCommand was introduced
Added the delete document to avoid broken urls and added a notice that
the document was moved to another location
Changed the code to remove references to Symfony Framework since it's
the standalone component
Updated references to the new document
Moved `versionadded` to the right section
Applied some suggestions
Applyed suggestions from @fabpot and @stof
Applied suggestions from Ryan
feature #3426 New Feature: Change the Default Command in the Console component (danielcsgomes)

This PR was merged into the master branch.

Discussion
----------

New Feature: Change the Default Command in the Console component

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | yes (symfony/symfony#9776)
| Applies to    | 2.5+
| Fixed tickets |

I followed the suggestion from @WouterJ in IRC on changing the `single_command_tool` and added the documentation for the new feature there.

Commits
-------

c1b2aad Applied suggestions from Ryan
5e97202 Applyed suggestions from @fabpot and @stof
c23f34e Applied some suggestions
012456d Moved `versionadded` to the right section
730985f Updated references to the new document
af9eac4 Changed the code to remove references to Symfony Framework since it's the standalone component
60e2b3e Added the delete document to avoid broken urls and added a notice that the document was moved to another location
11c7174 Added the version number where the setDefaultCommand was introduced
b29ab89 Documented the Change the Default Command in the Console component