[emacs] Add snippets for latex mode.

.emacs.d/snippets/latex-mode/case.yasnippet

@@ -0,0 +1,9 @@
+# -*- mode: snippet -*-
+# contributor: Mads D. Kristensen <madsdk@gmail.com>
+# key: case
+# group: math
+# name: \begin{cases} ... \end{cases}
+# --
+\begin{cases}
+$0 \\\\
+\end{cases}