Requested Changes for Editor Knossos Implementation (#129)

* placeholder

* max length & placeholder

* Accept editor comment conflict

* integrate requested features

* null check for ref

* Change prompt for image upload

* change filter for proper input blocking

* Add spoiler button

* change url of helper link

* shallow resource link style

* resource link inherit site style

* detach preview styling from markdown-body style

* remove sizing dependance on global styles

* Bump 0.6.5

package.json

@@ -1,7 +1,7 @@
 {
   "name": "omorphia",
   "type": "module",
-  "version": "0.6.4",
+  "version": "0.6.5",
   "files": [
     "dist"
   ],