Upgraded the dwmblocks patch for statuscmd which changes the signalling

mechanism from SIGUSR1 to SIGRTMIN which is likely to cause issues for
those that already have a working setup. A compatibility option has been
added which changes this back to SIGUSR1. Note that configuration was
also changed.

This was ref. reported issue #114.

patch/bar_dwmblocks.h

@@ -1,2 +1,2 @@
-static int getdwmblockspid();
-static void sigdwmblocks(const Arg *arg);
+static int getstatusbarpid();
+static void sigstatusbar(const Arg *arg);