Move khash & yopt to deps/

Both microlibraries come from another source, and are not maintained as
part of ncdu. This separation of src/ and deps/ makes the relation more
clear.

Makefile.am

@@ -1,3 +1,4 @@
+AM_CPPFLAGS=-I$(srcdir)/deps
 bin_PROGRAMS=ncdu
 
 ncdu_SOURCES=\
@@ -16,6 +17,8 @@ ncdu_SOURCES=\
 	src/util.c
 
 noinst_HEADERS=\
+	deps/yopt.h\
+	deps/khash.h\
 	src/browser.h\
 	src/delete.h\
 	src/dir.h\
@@ -23,10 +26,8 @@ noinst_HEADERS=\
 	src/exclude.h\
 	src/global.h\
 	src/help.h\
-	src/khash.h\
 	src/path.h\
-	src/util.h\
-	src/yopt.h
+	src/util.h
 
 
 man_MANS=ncdu.1

src/dir_mem.c

@@ -24,11 +24,12 @@
 */
 
 #include "global.h"
-#include "khash.h"
 
 #include <string.h>
 #include <stdlib.h>
 
+#include <khash.h>
+
 
 static struct dir *root;   /* root directory struct we're scanning */
 static struct dir *curdir; /* directory item that we're currently adding items to */

src/main.c

@@ -34,7 +34,7 @@
 #include <sys/time.h>
 #include <locale.h>
 
-#include "yopt.h"
+#include <yopt.h>
 
 
 int pstate;