Detect filename automatically based on class name

I propose we auto-guess php class name based on filename, where that class is stored.

For example "my_super_helper.php" file will contain "MySuperHelper" class and nothing other.

There are several benefits of this:

• no need to specify class name in unit config file (only class filename remains);
• developer will be forced to properly name class file to connect it's class to the system.

We'll make some presumptions, that:

• "eh" will transform to "EventHandler"
• "tp" will transform to "TagProcessor"
• all classes from "core" module, that are not event handler/tag processor should have "k" in front of their name

Before:

• UsersEventHandler, users_event_handler.php
• UserGroupsEventHandler, user_groups_eh.php
• kThemesHelper, themes_helper.php
• CustomFieldsTagProcessor, custom_fields_tag_processor.php

After:

• UserEventHandler, user_eh.php
• UserGroupEventHandler, user_group_eh.php
• kThemeHelper, theme_helper.php
• CustomFieldTagProcessor, custom_field_tp.php