1.3.0

*Fixes for Default Settings:
Default settings changes will no longer overwrite existing blocks. This was due to how Wordpress handles default block attributes.
*Add PracticeBird Deeplink block
Now an additional block is included to deep-link music sheets into our free PracticeBird app for practice!
*Updated to latest OSMD version:
-More performant rendering! 30-60% faster rendering times!
-Misc. bugfixes