Add cmake-format config file.

.cmake-format

@@ -0,0 +1,19 @@
+# -----------------------------
+# Options affecting formatting.
+# -----------------------------
+with section("format"):
+
+  # How wide to allow formatted cmake files
+  line_width = 120
+
+  # How many spaces to tab for indent
+  tab_size = 4
+
+# ------------------------------------------------
+# Options affecting comment reflow and formatting.
+# ------------------------------------------------
+with section("markup"):
+
+  # enable comment markup parsing and reflow
+  enable_markup = False
+