feat(directive): ng:focus, ng:blur

Added directives for focus and blur events.

Closes #1277
chore(ngdocs): fix improve button overlap
fix($compile): allow data: image URIs in img[src]

Ref: 1adf29af13890d61286840177607edd552a9df97

BREAKING CHANGE: img[src] URLs are now sanitized via a separate
    whitelist regex instead of sharing the whitelist regex with a[href].
    With this change, img[src] URLs may also be data: URI's matching
    mime types image/*.  mailto: URLs are disallowed (and do not make
    sense for img[src] but were allowed under the a[href] whitelist used
    before.)
docs(jqLite): document "$destroy" event
chore(resource): use minErr to throw exception
chore(sanitize): use minErr to throw exception
feat(Angular): provide minErr as public property

This allows us to use minErr in other modules, such as resource and sanitize.
test(ngRepeat): add a test for ngRepeat when using 'track by' and a filter
fix(core): parse URLs using the browser's DOM API