feature #4099 Composer installation verbosity tip (dannykopping)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #4099).

Discussion
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Composer installation verbosity tip

Added installation verbosity tip, for users with slow internet connections.

With love from slow South Africa 🌍

Commits
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f8d69d4 Added Composer installation tip

book/installation.rst

@@ -66,6 +66,10 @@ Distribution:
     To download the vendor files faster, add the ``--prefer-dist`` option at
     the end of any Composer command.
 
+    Add the ``-vvv`` flag to see everything that Composer is doing - this is
+    especially useful on a slow connection where it may seem that nothing is
+    happening.
+
 This command may take several minutes to run as Composer downloads the Standard
 Distribution along with all of the vendor libraries that it needs. When it finishes,
 you should have a directory that looks something like this:

cookbook/workflow/new_project_git.rst

@@ -26,7 +26,13 @@ git repository:
 
    .. code-block:: bash
 
-        $ php composer.phar create-project symfony/framework-standard-edition path/ '~2.3'
+        $ php composer.phar create-project symfony/framework-standard-edition path/ '~2.5'
+
+.. tip::
+
+    Add the ``-vvv`` flag to see everything that Composer is doing - this is
+    especially useful on a slow connection where it may seem that nothing is
+    happening.
 
    Composer will now download the Standard Distribution along with all of the
    required vendor libraries. For more information about downloading Symfony using

quick_tour/the_big_picture.rst

@@ -22,6 +22,12 @@ directory:
 
     $ composer create-project symfony/framework-standard-edition myproject/ '~2.3'
 
+.. tip::
+
+    Add the ``-vvv`` flag to see everything that Composer is doing - this is
+    especially useful on a slow connection where it may seem that nothing is
+    happening.
+
 .. note::
 
     `Composer`_ is the package manager used by modern PHP applications and the