fix #136, support watch exprs and two way bindings for component fields

test/data/expected/data_value_test.html.txt

Index: test/data/expected/data_value_test.html.txt
diff --git a/test/data/expected/data_value_test.html.txt b/test/data/expected/data_value_test.html.txt
deleted file mode 100644
index cb52fee127f1ef42b936d221f37549e316a0d2b1..0000000000000000000000000000000000000000
--- a/test/data/expected/data_value_test.html.txt
+++ /dev/null
@@ -1,49 +0,0 @@
-Blocked access to external URL http://dart.googlecode.com/svn/branches/bleeding_edge/dart/client/dart.js
-Blocked access to external URL http://dart.googlecode.com/svn/branches/bleeding_edge/dart/client/dart.js
-Content-Type: text/plain
-layer at (0,0) size 800x600
-  RenderView at (0,0) size 800x600
-layer at (0,0) size 800x140
-  RenderBlock {HTML} at (0,0) size 800x140
-    RenderBody {BODY} at (8,16) size 784x116
-      RenderBlock {P} at (0,0) size 784x20
-        RenderText {#text} at (0,0) size 545x19
-          text run at (0,0) width 434: "This test has two loops, each over two items, for a total of four different "
-          text run at (434,0) width 111: "greeting messages:"
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-        RenderText {#text} at (0,0) size 28x19
-          text run at (0,0) width 28: "hello"
-        RenderText {#text} at (28,0) size 8x19
-          text run at (28,0) width 8: ", "
-        RenderText {#text} at (36,0) size 35x19
-          text run at (36,0) width 35: "world"
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-          text run at (71,0) width 5: "!"
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-        RenderText {#text} at (0,0) size 28x19
-          text run at (0,0) width 28: "hello"
-        RenderText {#text} at (28,0) size 8x19
-          text run at (28,0) width 8: ", "
-        RenderText {#text} at (36,0) size 49x19
-          text run at (36,0) width 49: "universe"
-        RenderText {#text} at (85,0) size 5x19
-          text run at (85,0) width 5: "!"
-      RenderBlock {X-GREETER} at (0,76) size 784x20
-        RenderText {#text} at (0,0) size 10x19
-          text run at (0,0) width 10: "hi"
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-          text run at (10,0) width 8: ", "
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-          text run at (18,0) width 35: "world"
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-          text run at (53,0) width 5: "!"
-      RenderBlock {X-GREETER} at (0,96) size 784x20
-        RenderText {#text} at (0,0) size 10x19
-          text run at (0,0) width 10: "hi"
-        RenderText {#text} at (10,0) size 8x19
-          text run at (10,0) width 8: ", "
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-          text run at (18,0) width 49: "universe"
-        RenderText {#text} at (67,0) size 5x19
-          text run at (67,0) width 5: "!"
-#EOF