Bug 972712 (part 1) - Don't report short strings separately. r=till.

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extra : rebase_source : 631fe6137935cfb2fbfc3339406c5418d458ad38
Bug 972712 (part 2) - Shorten JS memory report descriptions. r=till.

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extra : rebase_source : 5acec546db5b3f62d4a88c301af282c53f8abaf4
Bug 972712 (part 3) - Rework notable string reporting. r=till.

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extra : rebase_source : 274c2ee9beafca5e464234f37e894967d20abb25
Bug 972712 (part 4) - Report script sources in more detail. r=till.

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extra : rebase_source : b28fc8f4ff791966cb784e1c12def58927d3e3d3
Bug 972712 (part 5) - Add BaseShape::clasp(). r=till.

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extra : rebase_source : 7eab6753c6c5b248446783132f84b07460aefef6
Bug 972712 (part 6) - Report objects and shapes by their class. r=till.

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extra : rebase_source : aa42a16006a3ef180056836215d497dba0eae383