New test for default type == string

See ZF1 issue for more: https://github.com/zendframework/zf1/issues/229
Updated AbstractValue to satisfy new test

See ZF1 issue for more: https://github.com/zendframework/zf1/issues/229
Fixed to use namespaces
Now passing tests.
Removed trailing spaces in tests/ZendTest/XmlRpc/ValueTest.php
Merge pull request #5375 from volftomas/patch-1

Fixes default type == string
Merge branch 'hotfix/5375'

Close #5375