Log Message:
Update textproc/erlang-p1_xml to 1.1.1.

Version 1.1.1
- Support for both rebar and rebar3
- Huge performance and memory improvements
- Normalize namespace prefixed elements
- Document how to run tests
- Architecture documentation in README.md
- Introduce Elixir Quickcheck tests
- Support C code coverage
- Better test case coverage
- Continuous integration with Travis CI and Coveralls
- Test refactoring
- Save cflags/ldflags passed to configure
- Move code for locating nif files to p1_utils package
- Improve code for locating .so part
- Do not check Expat presence via m4 macro

Version 1.1.0
- Initial release on Hex.pm