Changes

PR for editing fields in an EmbedBuilder (#335)
* added EmbedBuilder#getFields for editing the list of embed fields
modified related methods to not disturb EntityBuilder while still
providing checks

* Adjusted documentation for getFields()
setTitle(String, String) without a url parameter to avoid confustion
Updated setColor documentation to link to example
setTitle(String, String) to be considered as no url
 (commit: 50b260e)