Add snippets for zsh

zsh is a seperate filetype from sh in Vim. This uses the sh snippets
while changing the shebang-related snippets.

UltiSnips/zsh.snippets

@@ -0,0 +1,13 @@
+extends sh
+
+snippet #! "shebang" !
+#!/bin/zsh
+
+endsnippet
+
+snippet !env "#!/usr/bin/env (!env)" !
+#!/usr/bin/env zsh
+
+endsnippet
+
+# vim:ft=snippets: