fixed psl_str_to_utf8lower prototype
small doc format change
fixed authors name to UTF-8
removed ChangeLog (see NEWS for summarized changes)
started with libidn2 integration
more work on support for libidn, libidn2, libicu
added all combinations of runtime and builtin options
added code for all of runtime and builtin options
fixed libidn package names in .travis.yml
Merge tag '0.4.0' into develop
added unistring hint to configure --help
Merge branch 'develop'
Release v0.5.0
Merge branch 'master' into debian
prepare for 0.5.0-1 debian release
removed idn2 from build dependencies
added --enable-builtin and --enable-runtime