STYLE: use full path for decompositionMethods includes

- improves overall consistency and simplifies mpi-specific reuse
  (ie, ptscotchDecomp)

src/parallel/decompose/kahipDecomp/Make/options

 EXE_INC = \
     -I$(KAHIP_INC_DIR) \
-    -I../decompositionMethods/lnInclude
+    -I$(LIB_SRC)/parallel/decompose/decompositionMethods/lnInclude
 
 /*
  * KaHIP is usually compiled with openmp, but may be missing the

src/parallel/decompose/metisDecomp/Make/options

 EXE_INC = \
     -I$(METIS_INC_DIR) \
-    -I../decompositionMethods/lnInclude
+    -I$(LIB_SRC)/parallel/decompose/decompositionMethods/lnInclude
 
 LIB_LIBS = \
     -ldecompositionMethods \

src/parallel/decompose/ptscotchDecomp/Make/options

@@ -8,7 +8,7 @@ EXE_INC = \
     -I$(PTSCOTCH_INC_DIR) \
     -I$(SCOTCH_INC_DIR) \
     $(PFLAGS) $(PINC) \
-    -I../decompositionMethods/lnInclude
+    -I$(LIB_SRC)/parallel/decompose/decompositionMethods/lnInclude
 
 /*
  * The '-lscotch' is a slight hack:

src/parallel/decompose/scotchDecomp/Make/options

 EXE_INC = \
     -I$(SCOTCH_INC_DIR) \
-    -I../decompositionMethods/lnInclude
+    -I$(LIB_SRC)/parallel/decompose/decompositionMethods/lnInclude
 
 LIB_LIBS = \
     -ldecompositionMethods \