Use libdraw: add Xft and fallback-fonts support to graphics lib

- libdraw, util: add drw.{c,h}, util.{c,h} and update code.
- libdraw: fix drw_rect(): use w and h parameter.
- libdraw: print errstr if last character in string was ":" (sbase).
- libdraw: drw_clr_free() allow valid free(NULL).
- config.def.h: set default font to monospace.
- cleanup() on exit.
- LICENSE: update license string for dmenu -v to 2015.
- LICENSE: add myself to LICENSE

util.h

@@ -0,0 +1,7 @@
+/* See LICENSE file for copyright and license details. */
+
+#define MAX(A, B)               ((A) > (B) ? (A) : (B))
+#define MIN(A, B)               ((A) < (B) ? (A) : (B))
+#define BETWEEN(X, A, B)        ((A) <= (X) && (X) <= (B))
+
+void die(const char *errstr, ...);