Rename base plugin file to constant add-settings-links.php

[BrianHenryIE]

Versioning of the plugin is already handled by Git and by the plugin header: Version: 1.7.3.

If you were to continue renaming the plugin file each time, the plugin would get disabled each time it is updated. See the active_plugins option key:

array (
  0 => 'Add-Settings-Links/add-settings-linksv9.php',
  1 => 'hello.php',
)

Also, for referencing the plugin file in scripts, e.g. the i18n creation, it is much easier to have the name stay constant.