Merge pull request #4 from bobmaerten/master

Removed duplicate SQL line
rename event handler functions to prevent clash with other installed plagiarism plugins
also improve debugging on settings page
Update version.php

bump requires version and change maturity of code - has been tested.
Moodle 2.5 patch - invalidate config cache when saving settings (should tidy this up to use plagiarism_complilatio instead of plagiarism at some point
fix php warning
update capability names and add english strings
fix some deprec calls to context functions