Don’t lock globally when file changes occurs
Don’t lock globally when file changes occurs

Fixes potential problems where multiple files are changed at the same time or with plugins that are really slow.

Refs #235
1upon0/wintersmith,jmptrader/wintersmith,pridemusvaire/wintersmith,jnordberg/wintersmith,jmptrader/wintersmith,cwhatley/wintersmith,MorJar/wintersmith,pridemusvaire/wintersmith,MorJar/wintersmith