Commits cherry-picked to master

Hi folks,
The following WHATWG bugs have been merged into HTML5.1 Master branch. This brings the Master branch up to date as of SVN 8376.

Substantive:

[giow] (2) Make the case of an API call trying to navigate a browsing context that it can't navigate due to sandboxing throw a security exception rather than silently fail. (SVN 8370)
https://github.com/w3c/html/commit/0a18eb8914579381224aee7082d7e1ef14dee36b

[giow] (0) Define structured cloning for Map and Set (SVN 8374)
https://github.com/w3c/html/commit/8740d548b05f29d420ed28b69885b3e6eccc491c

[e] (0) Rearrange requirements for handling internal raw uncompiled handlers (SVN 8375)
https://github.com/w3c/html/commit/bfb3ca2c7a70927eb7a08035a38c1349b3fb6242

[giow] (3) Make content attribute event handlers work slightly more like in more browsers. (SVN 8376)
https://github.com/w3c/html/commit/a85bb98219b709608f10d7d3d1855e768007ef92

Editorial:

[e] (0) Clarification regarding 'The algorithm for deleting names' for dataset. (SVN 8371)
https://github.com/w3c/html/commit/7b9c6e658b85a43e355e4d8aaad8215608a098d2

[e] (0) ack for recent commits (SVN 8372)
https://github.com/w3c/html/commit/27accfb0bea8355c80e87edead1437ef2cc67641

[e] (0) Fix cross-references in structured clone algorithm (SVN 8373)
https://github.com/w3c/html/commit/dff3aca7e1302de74ce08217bd5c3bba7ccea8f2

Out of Scope:

[giow] (1) Make a.ping and area.ping use DOMSettableTokenList based on #whatwg feedback. Hopefully no content relies on their existing implementations; if they do let me know and we'll back this out. (SVN 8369)
https://github.com/w3c/html/commit/553046e07f0edd5909304a264aebc68ebec4f1df