extensions.tombfix.postConfig should be JSON Data #19

* Use JSON.parse() and JSON.stringify() instead of eval() and uneval()
Change trimReblogInfo to model.tumblr.trimReblogInfo

* Fix trimReblogInfo's description
v0.0.7

* Implement append content source for Tumblr
* extensions.tombfix.postConfig should be JSON Data
* Change extensions.tombfix.trimReblogInfo to extensions.tombfix.model.tumblr.trimReblogInfo