create snippets for use in emacs-yasnippet

plus more cleanup of main tidal file, and updated readme

snippets/b1drum1

@@ -0,0 +1,12 @@
+# -*- mode: snippet -*-
+# name: b1drum1
+# group: battery123
+# key: b1drum1
+# expand-env: (yas-indent-line 'fixed)
+# --
+-- @b1drum1
+d'drum $ cf $ stack [
+  -- every 4 (density 1.5) $ -- (2)
+  -- slow 2 $ s "peri [~ peri] ! ~", -- (1)
+  sound "~ psr:1"
+  ]