Change SDK/DartEditor versioning scheme to semantic versions.

dart/tools/VERSION

+# This file is used by tools/utils.py to generate version strings.
+# The numbers are changed as follows:
+#
+#  * New release cycle has begun (i.e. stable release was just made):
+#     - increase MINOR by 1
+#     - set "PATCH 0"
+#     - set "PRERELEASE 0"
+#     - set "PRERELEASE_PATCH 0"
+#
+#  * Doing a push-to-trunk from bleeding_edge:
+#    (The first push-to-trunk in the release cycle will set PRERELEASE to 1)
+#     - increase PRERELEASE by 1
+#     - set "PRERELEASE_PATCH 0"
+#
+#  * Doing a cherry-pick to trunk:
+#     - increase PRERELEASE_PATCH by 1
+#
+#  * Making a stable release (i.e. new stable branch):
+#     - set "PRERELEASE 0"
+#     - set "PRERELEASE_PATCH 0"
+#    The new stable release version will sort higher than the prereleases.
+#
+#  * Making cherry-picks to stable channel
+#     - increase PATCH by 1
+#
 CHANNEL be
-MAJOR 0
+MAJOR 1
 MINOR 1
-BUILD 2
 PATCH 0
+PRERELEASE 0
+PRERELEASE_PATCH 0