fix a couple little issues

1. don't display warnings when generating schema.rb, since it's just a
   lot of noise with no context
2. don't choke on 1.9 syntax in schema.rb
3. allow create_trigger to be called w/ a name and no options

lib/hair_trigger.rb

@@ -70,7 +70,7 @@ def current_migrations(options = {})
       if previous_schema = (options.has_key?(:previous_schema) ? options[:previous_schema] : File.exist?(schema_rb_path) && File.read(schema_rb_path))
         base_triggers = MigrationReader.get_triggers(previous_schema, options)
         unless base_triggers.empty?
-          version = (previous_schema =~ /ActiveRecord::Schema\.define\(:version => (\d+)\)/) && $1.to_i
+          version = (previous_schema =~ /ActiveRecord::Schema\.define\(.*?(\d+)\)/) && $1.to_i
           migrations.unshift [OpenStruct.new({:version => version}), base_triggers]
         end
       end

lib/hair_trigger/migration_reader.rb

@@ -50,6 +50,7 @@ def extract_method_call(exp)
       def generate_create_trigger(*arguments)
         arguments.unshift({}) if arguments.empty?
         arguments.unshift(nil) if arguments.first.is_a?(Hash)
+        arguments.push({}) if arguments.size == 1
         arguments[1][:compatibility] ||= HairTrigger::Builder.base_compatibility
         ::HairTrigger::Builder.new(*arguments)
       end

lib/hair_trigger/schema_dumper.rb

@@ -1,8 +1,12 @@
 module HairTrigger
   module SchemaDumper
     def trailer_with_triggers(stream)
+      orig_show_warnings = Builder.show_warnings
+      Builder.show_warnings = false # we already show them when running the migration
       triggers(stream)
       trailer_without_triggers(stream)
+    ensure
+      Builder.show_warnings = orig_show_warnings
     end
 
     def triggers(stream)
@@ -84,4 +88,4 @@ class << self
       end
     end
   end
-end
+end