fixes #46 by allowing podcasts with no description

fix #46

add #52

for #49. When creating a podcast note, syntax like {{podcast}}/{{title}}.md is now possible

add #49

bug caused when opening Obsidian with the plugin view open. The intersection observer wouldn't
detect intersection, so images wouldn't load.

fix #18

fix #17

support both playing local files and writing notes & creating timestamps on local files.