Deprecate diagonal tooltip classes

Fix modal backdrop overlaying the modal's scrollbar

Fix #14936: Use correct left/right and margin on tooltip arrows

Fixes #14916.

Fixes #14950.
Closes #15015 by merging it.

Use Jekyll data for Wall of Browser Bugs

Use autoprefixer for Customizer builds

Remove duplicate code from Customizer/Gruntfile by sharing it

Add event.relatedTarget + `data-*` example to Modal docs

Fixes #14245

Add Wall of Browser Bugs entry for #14972

Fix typo

Corrected spelling of the word "elements"

fix whitespace in js dropdown docs

Update Jekyll to v2.4.0 and rouge to v1.7.2.

Examples: Make use of the `footer` tag instead of a class.

Cover common contributor mistakes in CONTRIBUTING.md

Based on https://github.com/twbs/rorschach/tree/master/docs

Add Wall of Browser Bugs entry for #14409

Closes #14409.
[skip sauce]

Explain issue/PR bots in CONTRIBUTING.md

Customizer: listen to the right event for manual file selection in import

This reverts commit ea239691.

BootstrapCDN has now uploaded Bootstrap v3.3.0

Replace deprecated uses of .pull-left & .pull-right in .media docs

[skip sauce]
[skip validator]

Refs https://github.com/twbs/bootlint/pull/153
[skip sauce]

Closes #14941