Fixed specs to ensure #truthy? returns only true or false.

The specs don't read as nicely now, but they're more correct. Priorities.

spec/truthy_spec.rb

@@ -3,71 +3,71 @@
 describe 'truthiness' do
 
   specify 'false should not be truthy' do
-    false.should_not be_truthy
+    false.truthy?.should == false
   end
 
   specify 'nil should not be truthy' do
-    nil.should_not be_truthy
+    nil.truthy?.should == false
   end
 
   specify 'true should be truthy' do
-    true.should be_truthy
+    true.truthy?.should == true
   end
 
   specify 'a string should be truthy' do
-    'this is a string'.should be_truthy
+    'this is a string'.truthy?.should == true
   end
 
   specify 'even an empty string should be truthy' do
-    ''.should be_truthy
+    ''.truthy?.should == true
   end
 
   specify 'a string containing nothing but whitespace should still be truthy' do
-    '   		  '.should be_truthy
+    '   		  '.truthy?.should == true
   end
 
   specify 'a number should be truthy' do
-    1.should be_truthy
+    1.truthy?.should == true
   end
 
   specify 'zero is truthy' do
-    0.should be_truthy
+    0.truthy?.should == true
   end
 
   specify 'infinity is totally truthy' do
-    (1.0/0.0).should be_truthy
+    (1.0/0.0).truthy?.should == true
   end
 
   specify 'even a negative number is truthy' do
-    -5.should be_truthy
+    -5.truthy?.should == true
   end
 
   specify 'an array should be truthy' do
-    ['a', 1].should be_truthy
+    ['a', 1].truthy?.should == true
   end
 
   specify 'an empty array is truthy' do
-    [].should be_truthy
+    [].truthy?.should == true
   end
 
   specify 'an array containing only non-truthy elements: still truthy' do
-    [nil, false].should be_truthy
+    [nil, false].truthy?.should == true
   end
 
   specify 'a hash is truthy' do
-    { 'a' => 1 }.should be_truthy
+    { 'a' => 1 }.truthy?.should == true
   end
 
   specify 'an empty hash is truthy' do
-    {}.should be_truthy
+    {}.truthy?.should == true
   end
 
   specify 'an hash containing only non-truthy things: still truthy' do
-    { nil => false }.should be_truthy
+    { nil => false }.truthy?.should == true
   end
 
   specify 'an object is truthy' do
-    Object.new.should be_truthy
+    Object.new.truthy?.should == true
   end
 
 end