✅ Add RFC3454 data, to support offline testing

We generate `rfcs/rfc3454-stringprep_tables.json` from RFC3454, and
generate the regexps in both `lib/net/imap/stringprep/tables.rb` and
`lib/net/imap/stringprep/saslprep_tables.rb` using those tables
extracted from RFC3454.  The JSON data is also used to validate that the
regexps are still valid, as we use Unicode character classes which can
be updated every year, and thus with every new version of ruby.

However, this means that the test suite cannot be run offline (unless
you have previously downloaded RFC3454).  Adding the text version of
RFC3454 solves this issue.

Fixes #136.

Author: nevans

net-imap.gemspec

@@ -25,7 +25,7 @@ Gem::Specification.new do |spec|
   # Specify which files should be added to the gem when it is released.
   # The `git ls-files -z` loads the files in the RubyGem that have been added into git.
   spec.files         = Dir.chdir(File.expand_path('..', __FILE__)) do
-    `git ls-files -z 2>/dev/null`.split("\x0").reject { |f| f.match(%r{^(bin|test|spec|features)/}) }
+    `git ls-files -z 2>/dev/null`.split("\x0").reject { |f| f.match(%r{^(bin|test|spec|features|rfcs)/}) }
   end
   spec.bindir        = "exe"
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }