Update zend.mvc.services.rst

Fixed typo in view helper plugin manager class name.
Merge pull request #1062 in master
Merge pull request #1061 in master
Install sphinx via package manager
Specify specific versions of Python and Sphinx for Travis-CI build.
Install sphinx via package manager
Specify specific versions of Python and Sphinx for Travis-CI build.
Merge pull request #1065
Merge pull request #1056
Merge pull request #1056 in develop