Allow multiple results when asking questions

The original functionality is exactly the same if the `number-of-results` flag is 1 (the default). 

If you pass in --number-of-results > 1, you'll get more results now. 

	$ python howdoi.py print stack python
	import traceback
	
	def f():
	    g()
	
	def g():
	    for line in traceback.format_stack():
	        print line.strip()
	
	f()
	
	# Prints:
	# File "so-stack.py", line 10, in <module>
	#     f()
	# File "so-stack.py", line 4, in f
	#     g()
	# File "so-stack.py", line 7, in g
	#     for line in traceback.format_stack():
	
    $ python howdoi.py --number-of-results 2 print stack python
	
	----------------------
	Result 1
	
	import traceback
	
	def f():
	    g()
	
	def g():
	    for line in traceback.format_stack():
	        print line.strip()
	
	f()
	
	# Prints:
	# File "so-stack.py", line 10, in <module>
	#     f()
	# File "so-stack.py", line 4, in f
	#     g()
	# File "so-stack.py", line 7, in g
	#     for line in traceback.format_stack():
	
	
	----------------------
	Result 2
	
	>>> def f():
	...   def g():
	...     traceback.print_stack()
	...   g()
	...
	>>> f()
	  File "<stdin>", line 1, in <module>
	  File "<stdin>", line 4, in f
	  File "<stdin>", line 3, in g
	
	$ python howdoi.py --number-of-results 2 -p 2 print stack python
	
	----------------------
	Result 2
	
	>>> def f():
	...   def g():
	...     traceback.print_stack()
	...   g()
	...
	>>> f()
	  File "<stdin>", line 1, in <module>
	  File "<stdin>", line 4, in f
	  File "<stdin>", line 3, in g
	
	
	----------------------
	Result 3
	
	def install_xxx():
	   print("Installing XXX...      "),
	
	install_xxx()
	print "[DONE]"