Rework admin option-name-sort page to fix HTML syntax

 - fix missing `"` around html attributes
 - refactor repeated $_GET vars
 - remove old code
 - replace hardcoded button text with lang constant
Fixes #155 - remove fragments of entypo font
Remove obsolete references to register_globals
Non-static method systemChecker::getAdminDirectoryList() should not be called statically
Use of undefined constant: fileName
Uncaught file-not-found exception
NOTE: A future re-factoring might include renaming this class method so that code reviewers don't flag it as a clash with PHP reserved function names
Undefined variable $error_number
Undefined variable $remove_from_queryCache
Undefined variable: $db_prefix
Abbreviated ternary operator triggers same error.
Can't use abbreviated ternary operator here, else a boolean is returned.
Use of undefined constant ADMIN_NAME_MINIMUM_LENGTH
Undefined index: list_order
Fixes: Missing argument 5 for zen_update_user()
problem created in PR #168
Closes #184 - Stop making configure.php read-only
(after a period of open discussion)

(And, yes, this is intentionally mere commented-out, and may remain so for a period of deprecation, and then refactored out in a subsequent version.)
Upgrade minimum required PHP version to 5.4.0
... not only because 5.3 is EOL but also because we use features requiring 5.4.0 minimum
Merge pull request #177 from drbyte/option-name-sort-cleanup

Rework admin option-name-sort page to fix HTML syntax
Merge pull request #180 from drbyte/155-entypo-removal(b)

Fixes #155 - remove fragments of entypo font
Merge pull request #181 from drbyte/missing-constant

Use of undefined constant ADMIN_NAME_MINIMUM_LENGTH
Merge pull request #182 from drbyte/register-globals-removal

Remove obsolete references to register_globals
Merge pull request #183 from drbyte/add-to-168-cellnum

Fixes: Missing argument 5 for zen_update_user()
Merge pull request #185 from drbyte/disable-readonly-trigger

Closes #184 - Stop making configure.php read-only