Scheme: improve alignment for some snippets and add one UltiSnips snippet

UltiSnips/scheme.snippets

@@ -0,0 +1,8 @@
+###########################################################################
+#                            TextMate Snippets                            #
+###########################################################################
+snippet def
+(define ${2:(${1:name-and-args})}
+	${0:body})
+endsnippet
+# vim:ft=snippets:

snippets/scheme.snippets

@@ -1,36 +1,40 @@
 snippet +
 	(+ ${1}
-		${0})
+	   ${0})
 
 snippet -
 	(- ${1}
-		${0})
+	   ${0})
 
 snippet /
 	(/ ${1}
-		${0})
+	   ${0})
 
 snippet *
 	(* ${1}
-		${0})
+	   ${0})
 
 # Definition
 snippet def
-	(define (${1:name})
-		${0:definition})
+	(define ${1:name}
+		${0})
+
+snippet deff
+	(define (${1:name-and-args})
+		${0:body})
 
 # Definition with lambda
 snippet defl
 	(define ${1:name}
-		(lambda (x)(${0:definition})))
+		(lambda (${2:args}) (${0:body})))
 
 # Condition
 snippet cond
 	(cond ((${1:predicate}) (${2:action}))
-		((${3:predicate}) (${0:action})))
+	      ((${3:predicate}) (${0:action})))
 
 # If statement
 snippet if
 	(if (${1:predicate})
-		(${2:true-action})
-		(${0:false-action}))
+	    (${2:true-action})
+	    (${0:false-action}))