Adds warnings for uncallable handlers in hooks/events.
Adds units for the warnings.
Injects logger into events/hooks services.
Ensures logger, events, and hooks are setup in right order in service provider.
Fixes small bug in DI container.
feature(views) Eases extending the input/view view

In order to extend forms *outside* the form element, devs must extend the 
input/form view, however it's a bit cumbersome to determine the current
action because you have to extract it from the "action", which is a URL. This
gives the extending view the raw action name.

Fixes #6129
security(http): Adds anti-clickjacking header when serving pages

Adds a header that prevents framing pages from different domains in
modern browsers. A plugin hook allows disabling/altering the headers
sent.

Fixes #6098
Merge pull request #6265 from mrclay/uncallable_handlers

Adds warnings for uncallable handlers in hooks/events.
Merge pull request #6348 from mrclay/6129

Eases extending the input/view view
docs(hooks): Corrects docs syntax error
Merge pull request #6380 from Srokap/pr/6331
feature(output): Added second parameter to elgg_strip_tags.
Merge pull request #6324
fix(views): Correct default title for confirmlink

Wrong key was used from $vars when 'title' was not passed.
It now correctly defaults to 'confirm'.

Closes #6375
Merge pull request #6376 from hellekin/fix-6375

Fix wrong key from $vars (closes #6375)
chore(blog): simplify the blog js

Clean up the blog autosave JS and action

Refs #6368
chore(blog): replace save_draft.php with its js equivalent

Replaces save_draft.php with its js equivalent and reflects the changes in plugin init

Refs #6368
chore(blog): refactor auto save action and adds missing container references

Refactors the auto save action to be more readable, adds action description, adds container logic, removes unused variables

Refs #6368
chore(blog): correct syntax and combine jQuery selects

Corrects comparison operand, adds missing semincolon, combines jQuery operators, exposes update interval as a variable

Fixes #6368
Merge branch 'blog-js' of https://github.com/hypeJunction/Elgg into blog-js