try to fix escaping again

this time by taking out all my own escaping code as
I found out about the WP function 'wp_magic_quotes()'
which is called every at the beginning of each page
So ... I shouldn't have to worry about escaping at all.
We'll see.
bump version number
allow deletion of unused assets

fixes #100
refactor episode_asset::is_deletable
enhancement: if an asset can't be deleted, display the exact reasons

issue #100
enhancement: allow deletion of in-use assets

issue #100
fix PodloveModelEpisodeAsset::active_media_files