Add syntax files from upstream vim repository

compiler/checkstyle.vim

@@ -0,0 +1,23 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'vim') == -1
+  
+" Vim compiler file
+" Compiler:	Checkstyle
+" Maintainer:	Doug Kearns <dougkearns@gmail.com>
+" Last Change:	2013 Jun 26
+
+if exists("current_compiler")
+  finish
+endif
+let current_compiler = "checkstyle"
+
+if exists(":CompilerSet") != 2		" older Vim always used :setlocal
+  command -nargs=* CompilerSet setlocal <args>
+endif
+
+CompilerSet makeprg=java\ com.puppycrawl.tools.checkstyle.Main\ -f\ plain
+
+" sample error: WebTable.java:282: '+=' is not preceeded with whitespace.
+"		WebTable.java:201:1: '{' should be on the previous line.
+CompilerSet errorformat=%f:%l:%v:\ %m,%f:%l:\ %m,%-G%.%#
+
+endif