puzzles: remove unnecessary files from the src/ directory.

This updates the resync.sh script to be more intelligent about which files
it copies from the upstream tree. It now attempts some rudimentary parsing
of the puzzles CMakeLists.txt file to figure out which files are actually
necessary, and copies only those.

This adds a new SOURCES.rockbox source file list for the Rockbox-specific
parts of the port.

Change-Id: I461f87ac712e3b2982dcbb0be9d70d278384a4e7

apps/plugins/puzzles/SOURCES

@@ -1,33 +1,29 @@
+/* Auto-generated by resync.sh */
 rockbox.c
 rbwrappers.c
 rbmalloc.c
 lz4tiny.c
 
+/* puzzles core sources */
 src/combi.c
 src/divvy.c
 src/drawing.c
 src/dsf.c
 src/findloop.c
 src/grid.c
+src/hat.c
 src/latin.c
 src/laydomino.c
 src/loopgen.c
-/*src/malloc.c*/ /* we have our own */
 src/matching.c
 src/midend.c
 src/misc.c
-src/penrose.c
 src/penrose-legacy.c
-src/printing.c
+src/penrose.c
 src/random.c
 src/sort.c
+src/spectre.c
 src/tdq.c
 src/tree234.c
 src/version.c
-
-src/hat.c
-src/spectre.c
-
-#ifdef COMBINED
-src/list.c
-#endif
+src/printing.c