* Renamed normalise.cc' -> build.cc', `storeexprs.cc' ->

`derivations.cc', etc.
* Store the SHA-256 content hash of store paths in the database after
  they have been built/added.  This is so that we can check whether
  the store has been messed with (a la `rpm --verify').
* When registering path validity, verify that the closure property
  holds.

src/libstore/Makefile.am

@@ -1,18 +1,18 @@
 noinst_LIBRARIES = libstore.a
 
 libstore_a_SOURCES = \
- store.cc store.hh storeexpr.cc storeexpr.hh \
- normalise.cc misc.cc normalise.hh \
+ store.cc store.hh derivations.cc derivations.hh \
+ build.cc misc.cc build.hh \
  globals.cc globals.hh db.cc db.hh \
  references.cc references.hh pathlocks.cc pathlocks.hh \
- gc.cc gc.hh storeexpr-ast.hh
+ gc.cc gc.hh derivations-ast.hh
 
-EXTRA_DIST = storeexpr-ast.def storeexpr-ast.cc
+EXTRA_DIST = derivations-ast.def derivations-ast.cc
 
 AM_CXXFLAGS = -Wall \
  -I.. ${bdb_include} ${aterm_include} -I../libutil
 
-storeexpr-ast.cc storeexpr-ast.hh: ../aterm-helper.pl storeexpr-ast.def
-	$(perl) ../aterm-helper.pl storeexpr-ast.hh storeexpr-ast.cc < storeexpr-ast.def
+derivations-ast.cc derivations-ast.hh: ../aterm-helper.pl derivations-ast.def
+	$(perl) ../aterm-helper.pl derivations-ast.hh derivations-ast.cc < derivations-ast.def
 
-storeexpr.cc: storeexpr-ast.hh
+derivations.cc: derivations-ast.hh