Migrate to Path::Tiny instead of File::Slurp

[plicease]

This uses Path::Tiny instead of File::Slurp. It fixes the rt127449. https://rt.cpan.org/Ticket/Display.html?id=127449 . File::Slurp has some problems as discussed here: http://blogs.perl.org/users/leon_timmermans/2015/08/fileslurp-is-broken-and-wrong.html

Though I did make an attempt to get File::Slurp to use the correct encodings with this patch:

diff --git a/lib/Test/PerlTidy.pm b/lib/Test/PerlTidy.pm
index 1fd7616..75fdb1a 100644
--- a/lib/Test/PerlTidy.pm
+++ b/lib/Test/PerlTidy.pm
@@ -67,7 +67,7 @@ sub is_file_tidy {
 
     # If there were perltidy errors report them and return.
     $stderr_fh->seek( 0, 0 );
-    my $stderr = read_file($stderr_fh);
+    my $stderr = read_file( $stderr_fh, { binmode => ':utf8' } );
     if ($stderr) {
         unless ($MUTE) {
             $test->diag("perltidy reported the following errors:\n");
@@ -167,7 +167,7 @@ sub load_file {
     return unless -f $filename;
 
     # Slurp the file.
-    my $content = read_file($filename);
+    my $content = read_file( $filename, { binmode => ':utf8' } );
     return $content;
 }
 

it works, but it gives some pretty annoying warnings:

# The file 't/not_tidy.t' is not tidy
# +--+----------------------------------+-----------------------------------+
# | 1|use utf8;                         |use utf8;                          |
# * 2|use  strict;  # \x{706b}\x{96de}  |use strict;    # \x{706b}\x{96de}  *
# | 3|use warnings;                     |use warnings;                      |
# | 4|use Test::More;                   |use Test::More;                    |
# | 5|                                  |                                   |
# +--+----------------------------------+-----------------------------------+

#   Failed test ''t/not_tidy.t''
#   at t/exclude_perltidy.t line 11.
sysread() is deprecated on :utf8 handles. This will be a fatal error in Perl 5.30 at /home/ollisg/.perlbrew/libs/perl-5.29.3@dev/lib/perl5/File/Slurp.pm line 179.
sysread() is deprecated on :utf8 handles. This will be a fatal error in Perl 5.30 at /home/ollisg/.perlbrew/libs/perl-5.29.3@dev/lib/perl5/File/Slurp.pm line 179.
sysread() is deprecated on :utf8 handles. This will be a fatal error in Perl 5.30 at /home/ollisg/.perlbrew/libs/perl-5.29.3@dev/lib/perl5/File/Slurp.pm line 179.
sysread() is deprecated on :utf8 handles. This will be a fatal error in Perl 5.30 at /home/ollisg/.perlbrew/libs/perl-5.29.3@dev/lib/perl5/File/Slurp.pm line 179.
t/exclude_perltidy.t .. 12/12 # Looks like you failed 1 test of 12.