Added UUIDs to timestamps, refactored the build process

* Added UUIDs to `ts_entry` records. Updated `ts_json:construct_record` to
  respond to `uuid` member properties if present. UUIDs are not required by the
  strict parsing functions in `ts_json` because the client will make a request
  with no UUID if it is a purely new timestamp. IN fact, this is the normal
  case. The UUID is only present when another tool is syncing its copy of this
  timeline wand adding entries that it has created and assigned UUIDs to.
* `ts_entry:new` will create a UUID for a new entry if it does not already have
  one.
* Restructured the build process to put all build artifacts into a dedicated
  `build` subdirectory, instead of mising them in an amongst the source code.
* Added the `uuid` module to the project. It can be found at

      https://gitorious.org/avtobiff/erlang-uuid

* Rewrote asset URLs to use relative paths instead of absolute paths. Relative
  paths are correct in this case, becuase assets always live alongside the HTML
  pages. This change was needed to accomodate the new organization of the JDB
  Labs dev environment, where all projects live under subdirectories of the
  same virtual server instead of subdomains.
* Tweaked the timestamp entry fields in the web UI to save when the field is
  blurred, not just when <Enter> or <Ctrl>-<Enter> is pressed (though those
  still work).

Makefile

@@ -1,11 +1,11 @@
 MODS = $(wildcard src/*.erl)
-BEAMS = $(MODS:src/%.erl=ebin/%.beam)
+BEAMS = $(MODS:src/%.erl=build/ebin/%.beam)
 TEST_MODS = $(wildcard test/*.erl)
-TEST_BEAMS = $(TEST_MODS:test/%.erl=test/%.beam)
+TEST_BEAMS = $(TEST_MODS:test/%.erl=build/test/%.beam)
 TS_ROOT=/usr/local/var/yaws/jdb-labs.com/timestamper
 CWD = `pwd`
 
-default: compile
+default: build
 
 all : compile test
 
@@ -17,10 +17,10 @@ test : start-test-server run-test stop-test-server
 
 test-shell : compile compile-test config-yaws-dev
 	@echo Starting an interactive YAWS shell with test paths loaded.
-	@yaws -i --pa test --id test_inst
+	@yaws -i --pa build/ebin --pa build/test --id test_inst
 
 run-test : compile compile-test config-yaws-dev
-	@erl -pa ./ebin -pa ./test -run timestamper_api_tests test -run init stop -noshell
+	@erl -pa ./build/ebin -pa ./build/test -run timestamper_api_tests test -run init stop -noshell
 
 start-test-server :
 	@yaws -D --id test_inst
@@ -29,28 +29,30 @@ stop-test-server :
 	@yaws --stop --id test_inst
 
 clean:
-	rm -rf ebin/* erl_crash.dump test/*.beam
+	rm -rf build
 
 init:
-	-mkdir ebin
+	-mkdir -p build/ebin
 
-ebin/%.beam : src/%.erl
-	erlc -W -o ebin $<
+build/ebin/%.beam : src/%.erl
+	erlc -W -o build/ebin $<
 
-test/%.beam : test/%.erl
+build/test/%.beam : test/%.erl
 	@echo Compiling sources...
-	erlc -W -o test $<
+	erlc -W -o build/test $<
+
+build: compile
+	-mkdir -p build/include
+	cp -r www build
+	cp lib/* build/ebin
+	cp src/ts_db_records.hrl build/include
+	cp yaws.prod.conf build/yaws.conf
 
 deploy: compile
 	@service yaws stop
 	@echo Removing existing artifacts.
 	- @rm -r $(TS_ROOT)
 	@echo Copying current artifacts.
-	@mkdir -p $(TS_ROOT)
-	@cp -r www $(TS_ROOT)
-	@cp -r ebin $(TS_ROOT)
-	@mkdir $(TS_ROOT)/include
-	@cp -r src/ts_db_records.hrl $(TS_ROOT)/include/.
-	@cp yaws.prod.conf $(TS_ROOT)/yaws.conf
+	@cp -r build $(TS_ROOT)
 	@service yaws start
 	@echo Done.