re-added html5shiv as the style stopped working on IE8 after I removed
it.
Merge branch 'jsdoc-improvements' into jsdoc-index-filtering-support
Merge commit 'ba93ca08813d89e79927bf514208c8a994c7984d' into jsdoc-index-filtering-support

Conflicts:
	brjs-sdk/build-resources/includes/sdk/jsdoc-toolkit-resources/jsdoc-toolkit/templates/default/tmpl/layout.tmpl
Use a PNG instead of an SVG for the 'x' button so that it can be viewed
in IE8.
Prevent IE8 from trying to submit when the enter key is pressed.
Clean up how we are doing the browser specific fix-ups so they are only
applied on the relevant browsers.
Work around the bug that occurs in IE10 and below (pressing enter in a
text box causes the first button in the same form to be clicked) by
explicitly wrapping in a <form/> tag in case other buttons are added to
the page (we do this in the BladeRunnerJS template), and ensuring that
the other button in the same form is not considered to be a submit
button.

Since explicitly wrapping in a <form/> causes Chrome to submit when you
press enter, I also added code to prevent this from occurring.
fix all linting errors except 'no-use-before-define', since these might
cause merge conflicts if mixed in with the other error fixes.
fixed remaining linting errors.
Merging changes from 'index-filtering-support' branch