Added notes to block-level function declaration

Just some notes clarifying that this feature was indeed discouraged in
ES5, in case people are confused by its inclusion in the ES6 table.
Fixed whitespace in HTML files
Fixes ES5 and non-standard pages in IE 8

The ES5 and non-standard pages should now work in IE 8 again.
(The ES6 page, puzzlingly, seems to make it freeze or crash. Oh well,
it's almost midnight.)

Fixes include:
* Fallback for hsl() colours
* "Show obsolete browsers" checkbox works again
* Fallback for opacity when selecting a column
* Tooltips work again (incorrectly uses String#trim and Array#forEach)
Fixed syntax error in Symbol.hasInstance test

Accidentally used "class" as an identifier.
Merge pull request #242 from webbedspace/hasinstance

Fixed a syntax error in Symbol.hasInstance test
Merge pull request #238 from webbedspace/blockfunction-note

Added notes to block-level function declaration
Merge pull request #235 from webbedspace/gh-pages

Fixes ES5 and non-standard pages in IE 8
Implemented browser results interpolation

Now, if a result from a browser's version is not different from that of
its previous version, the result need not be recorded in the data files.
Instead, build.js will copy the result over automatically.
I've thus cleared out all unnecessary lines from data-es6.js. This has
resulted in a large diff, but you may observe the es6/index.html diff to
see that little has changed w/r/t the output results.

Note: browsers are determined to be the same version by comparing their
"full" string. As a result, certain older Chrome versions now have the
"full" string "Chrome, Opera", even though they predate Opera 15.

ALSO:
* Fixed a few Chrome and Firefox results as per #239.
* Fixed some older Firefox results that referenced "firefox28" instead
of "firefox27" (which comprises both 27 and 28).