fix rename of getTasksForWorkspace to getTasksInWorkspace

Commit 770778c60396c2632b2ea19a0395b170115ee9ad changed the name of the
method, this commit fixes the get-workspaces.php example
Add the getTeams command for Asana organizations

With the new organizations feature it's now possible a workspace might be
an organization. Organizations can contain multiple teams which you can get
with the getTeams(array('organization-id' => $id)) command.
 * Added example to get-workspaces.php of getting teams in an organization
workspace
Add the team field when creating a project in an organization workspace

If the workspace for your project is an organization, you must also
supply a team to share the project with.
 * Added a commented example to the projects.php example script
Added content-type headers to override utf8 addition by guzzle 3.4.2

Guzzle 3.4.2 defaults to setting utf-8 for the Content-Type header on Posts
in this commit:
https://github.com/guzzle/guzzle/commit/026a68286dee6ce6c7e5f76baa4543acc25d1573.
However Asana returns 400 Bad Requests when trying to use this utf-8 header.
This commit overrides this header for all POSTS and PUT's
[Deps] Update guzzle to 3.4.3 and remove unneeded symfony components

The symfony components are not used, so can be removed.
Merge branch 'guzzle-update' for support 3.4.2 and up