added some more vim script snippets

snippets/vim.snippets

@@ -1,8 +1,13 @@
+snippet header
+	" File: ${1:`expand('%:t')`}
+	" Author: ${2:`g:snips_author`}
+	" Description: ${3}
+	${4:" Last Modified: `strftime("%B %d, %Y")`}
 snippet guard
-	if exists('${1:did_`expand('%:t:r')`}') || &cp
+	if exists('${1:did_`Filename()`}') || &cp${2: || version < 700}
 		finish
 	endif
-	let $1 = 1${2}
+	let $1 = 1${3}
 snippet f
 	fun ${1:function_name}(${2})
 		${3:" code}
@@ -12,7 +17,7 @@ snippet for
 		${3:" code}
 	endfor
 snippet wh
-	wh ${1:condition}
+	while ${1:condition}
 		${2:" code}
 	endw
 snippet if