Allow for tabs or spaces as indentation

This signals a move to allowing for normal Ruby indentation (2 space
soft tabs). This change will check files for indentation of spaces or of
tabs, since we don't want to fail out all modules quite yet.

For more, see
https://github.com/rapid7/metasploit-framework/wiki/Indentation-Standards
where all details of the conversion plan will be documented in order to
minimize the amount of whitespace conflict we are sure to encounter over
this conversion.

tools/msftidy.rb

@@ -353,8 +353,10 @@ class Msftidy
 				warn("Spaces at EOL", idx)
 			end
 
-			if (ln.length > 1) and (ln =~ /^([\t ]*)/) and ($1.include?(' '))
-				warn("Bad indent: #{ln.inspect}", idx)
+			# Allow tabs or spaces as indent characters, but not both.
+			# This should check for spaces only on October 8, 2013
+			if (ln.length > 1) and (ln =~ /^([\t ]*)/) and ($1.match(/\x20\x09|\x09\x20/))
+				warn("Space-Tab mixed indent: #{ln.inspect}", idx)
 			end
 
 			if ln =~ /\r$/