Update TinyMCE to 4.3.6 and 4.3.7

[azaozz]

Was released earlier today. Changelog: ​https://github.com/tinymce/tinymce/blob/master/changelog.txt. Has several bugfixes, new custom event and setting to control the warning about switching to the plain text paste mode.

[azaozz]

In 36798:

TinyMCE: update to 4.3.6. Changelog: ​https://github.com/tinymce/tinymce/blob/master/changelog.txt.

Fixes #36035.

[azaozz]

In 36799:

TinyMCE: fix the close button position in the paste in text mode warning.

See #36035.

[azaozz]

In 36803:

TinyMCE: update to 4.3.7. Has few bug/regression fixes. Changelog: ​https://github.com/tinymce/tinymce-dist/blob/4.3.7/changelog.txt.

Fixes #36035.

[azaozz]

In 36857:

TinyMCE:

• Fix the icon for the native dialogs close button.
• Highlight the button on :focus.

See #36035.