Make the Perl generator use non-hardcoded namespaces.

Make the Perl generator use non-hardcoded namespaces.

- Make the Perl generator use program->get_namespace("perl")
  instead of program->get_perl_package()
- Eliminate the explicit "perl_package" in t_program.
- Deprecate the perl_package token.
- Update example .thrift files and syntax files.

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665624 13f79535-47bb-0310-9956-ffa450edef68