Add static declarations in Loader::library()

Add `static` declarations in `Loader::library()`

Not doing `element` do to this issue in themes
Add static declarations to methods in Object

Add `static` declarations to methods in `Object`
Check for Undefined index if no args

Check for Undefined index if no arguments
Avoid passing undefined offset `$cl[2]`

Avoid passing undefined offset `$cl[2]` in autoloader

- Change to `array_slice()`
Add static declaration to `Cache::key()`

Add static declaration to `Cache::key()`
Add static keyword to `PermissionKey::validate()`

Add static keyword to `PermissionKey::validate()`
Avoid undefined index on $_SESSION value checks

Avoid undefined index on $_SESSION value checks

- Check `isset()` on `$_SESSION['uID']` and $_`SESSION['uName']`
Add static declaration `checkUserForeverCookie`

Add static declaration to `User::checkUserForeverCookie()`
Avoid undefined index `$_COOKIE` value

Avoid undefined index `$_COOKIE['ccmUserHash']` in
`User::checkUserForeverCookie()`
Check if permission key category exists

Check if permission key category exists in
`PermissionKeyCategory::getByHandle()` and explicitly return false if
not found insread of null-ish falsey
Avoid undefined index in startup/process

Avoid undefined index at very top of startup/process
Avoid undefined index in $autoloadClasses

Avoid undefined index in $autoloadClasses in
`Loader::getFileFromCorePath()`

- Check with `array_key_exists()`
- Remove extra array copy to `$classes`
Add static declaration to `Loader::controller()`

Add static declaration to `Loader::controller()`
Add static delcaration to `View::url()`

Add static delcaration to `View::url()`
Add static declaration to `populateCategories`

Add static declaration to `PermissionKeyCategory::populateCategories()`
Check if event key exists before reading it

Check if event key exists before reading it

- Check `registeredEvents` for key and return empty array()
- remove `is_array` check as no longer needed
Add static declaration to `View::getInstance()`

Add static declaration to `View::getInstance()`
Avoid undefined index `$_COOKIE['ccmUserHash']`

Avoid undefined index `$_COOKIE['ccmUserHash']`
Merge pull request #1398 from mkly/get_stricter_1

Get stricter 1