fix(notification): extract notification summary from $params

Fixes #6885
docs(notifications): Adds docs for  'object', 'action' and 'summary' params used by notify_user()
Merge pull request #7066 from juho-jaakkola/notification-summary

Extract summary from $params in notify_user()
feature(notifications): site_notification about an annotation can now have an URL

Fixes #7055
feature(likes): improves compatibility with notification plugins

This allows for example site_notifications about new likes to include a link to the liked entity.

Refs #7055
Merge pull request #7064 from juho-jaakkola/site_notifications

Improves notifications about new annotations
docs(js): corrects function name to shim AMD modules

Fixes #7072
Merge pull request #7075 from PerJensen/docs_js_issue

docs(js): corrects function name to shim AMD modules
chore(travis): Stop downloading composer locally

Travis PHP 5.3+ environments come with composer pre-installed already
Merge pull request #7077 from ewinslow/travis-composer

chore(travis): Stop downloading composer locally
docs(all): fixes typos and improves readability
fix(views): respect icon_sizes config values when rendering icons

Remove hard-coded references to available icons sizes and use global icon_sizes config values and keys instead
Merge pull request #7088 from hypeJunction/icon-sizes

fix(views): respect icon_sizes config values when rendering icons
docs(cron): adds RST documentation about cron jobs

Converts wiki cron page to RST and references cron in Upgrading docs

Refs #6884
docs(all): improves formatting and comprehensibility of docs

Reworded some paragraphs to make more sense to new users. Applied formatting to some lists and paragraphs
Merge pull request #7087 from hypeJunction/docs

Fixes typos and adds cron RST docs
Merge