Fixing unicode problem in test _print_diff()
Using standart pragmas in .pm files in xt directory
Fixing warning in t/_print_diff in perl-5.8.9

Before this commit perl-5.8.9 (and only this version of Perl) showed:

    Use of uninitialized value in open at t/_print_diff.t line 61.
Switched to Dist::Zilla
0.05