Update user_agents.php

Added the PS Vita User Agent to the list.
Made set_error() method DRY.
Reverted indenting spaces back to tabs.

(My fault - Sorry!)
Fix for extending classes in a subdirectory (e.g. drivers)
fix typos in Parser.php
Logging functions: level parameter is not optional

This parameter cannot be optional, as the following parameter is mandatory.

Also completed the corresponding documentation.
Fix a docblock in Loader class
Do not trigger a possible custom autoloader, as it is irrelevant here

These were the last two calls of class_exists() without the $autoloader = FALSE argument.
Adds a few new lines to note directive to fix a build error in the docs.
Removes an obstacle to building the docs.
Merge pull request #2440 from vlakoff/develop

Logging functions: level parameter is not optional
Merge pull request #2441 from vlakoff/develop-2

Fix a docblock in Loader class
Merge pull request #2442 from vlakoff/develop-3

Do not trigger a possible custom autoloader, as it is irrelevant here
The date_range() function is a bit broken
Neither $unix_time nor $start_date were defined here

Signed-off-by: Rasmus Lerdorf <rasmus@php.net>
It looks like this should be $alter_type here

Signed-off-by: Rasmus Lerdorf <rasmus@php.net>
$element not $focus there
and you can't have required params after an optional one

Signed-off-by: Rasmus Lerdorf <rasmus@php.net>
Required arg in between optional ones

Signed-off-by: Rasmus Lerdorf <rasmus@php.net>
Required args after optional ones

Signed-off-by: Rasmus Lerdorf <rasmus@php.net>
values_parsing() only takes 1 arg

Signed-off-by: Rasmus Lerdorf <rasmus@php.net>
highlight_code() doesn't take an ENT_QUOTES arg

Signed-off-by: Rasmus Lerdorf <rasmus@php.net>