differences

(not other values which PHP evaluates to false)

To negate a config value, prefix the value with an '!'.

E.g. to disable recognition of the gopher scheme
!gopher

This applies to:
- scheme
- stopwords

This applies to:
- acronyms
- entities
- interwiki
- mime
- smileys

This was previously carried out in three separate places. Refactor
that code to use the new function.

Update tpl_pageTitle test to use a manager level admin plugin.

add unit test coverage

This is a quick fix in advance of the library being updated to
the latest & PHP7 compatible version.

- replace PHP4 style class constructor function names (based on
  class name) with php 5 __construct()
Also remove some '&' reference operators used with objects
And add some object type hints

    See Issue #1149
    - Show 'admin' or the admin plugin name for admin functions
    - Show action name for user & site actions, e.g. login, sitemape
    - Show page name + action for page actions, e.g. changes, backlinks
    - Show a utf8 pen glyph when editing
    - Otherwise show the page name (as previously)

This reverts commit c2fbf986.

See Issue #1149
- Show 'admin' or the admin plugin name for admin functions
- Show action name for user & site actions, e.g. login, sitemape
- Show page name + action for page actions, e.g. changes, backlinks
- Show a utf8 pen glyph when editing
- Otherwise show the page name (as previously)