Comment out postgres-pr dependencies (fixes maxlapshin#80)

This dependency is only used if RUBY_ENVIRONMENT=="JAVA",
which is not the case for me.

Author: Brett Beutell

Diff for: Gemfile

@@ -2,7 +2,7 @@ source 'https://rubygems.org'
 
 gem 'rake', '~> 10.3'
 gem 'mysql-pr', '~> 2.9'
-gem 'postgres-pr', '~> 0.6'
+# gem 'postgres-pr', '~> 0.6'
 
 platforms :jruby do
   gem 'activerecord'

Diff for: lib/mysqltopostgres.rb

@@ -1,7 +1,7 @@
 
 if RUBY_PLATFORM == 'java'
   require 'active_record'
-  require 'postgres-pr/postgres-compat'
+  # require 'postgres-pr/postgres-compat'
 else
   require 'pg'
   require 'pg_ext'

Diff for: mysqltopostgres.gemspec

@@ -82,7 +82,7 @@ Gem::Specification.new do |s|
   ]
 
   s.add_dependency('mysql-pr', ['~> 2.9'])
-  s.add_dependency('postgres-pr', ['~> 0.6'])
+  # s.add_dependency('postgres-pr', ['~> 0.6'])
   s.add_dependency('test-unit', ['~> 2.1'])
 
   if RUBY_PLATFORM == 'java'