indent with tabs not spaces

Found these with:
git grep "^  " $(find -type  f -name \*.hs) |grep -v ':  where'

Unfortunately there is some inline hamlet that cannot use tabs for
indentation.

Also, Assistant/WebApp/Bootstrap3.hs is a copy of a module and so I'm
leaving it as-is.

Types/Crypto.hs

@@ -62,7 +62,7 @@ calcMac
 	:: Mac          -- ^ MAC
 	-> L.ByteString -- ^ secret key
 	-> L.ByteString -- ^ message
-  -> String	  -- ^ MAC'ed message, in hexadecimals
+	-> String       -- ^ MAC'ed message, in hexadecimal
 calcMac mac = case mac of
 	HmacSha1   -> showDigest $* hmacSha1
 	HmacSha224 -> showDigest $* hmacSha224