MyAlerts 1.04 compatible, subscriptions alert added

Subscriptions alerts seem to work fine!
Readme update
Update pluginspack.php
Merge pull request #5 from JordanMussi/patch-1

Correct site link
Merge remote-tracking branch 'refs/remotes/upstream/master'
Fixed #6
Fixed #7 (untested, but should work) and commented some lines of code to help other devs understanding something
Improved the use of "file_exists"
Merge pull request #8 from JN-Jones/development

Merge pull request #8 from JN-Jones/development
Added support of my Announcement Plugin