Release share v0.18.0 (2020-08-06)

===  Breaking changes

*  big: add global flag MarshalJSONAsString

   MarshalJSONAsString define the default return behaviour of MarshalJSON().
   If its true (the default) the returned JSON format will encapsulated in
   double quote, as string instead of as numeric.

*  dns: refactoring resource record fields

*  http: do not return error based on response code

   The error in doRequest should be about connection error, everything
   else should be handled by user.

*  http: allow setting response type when registering PUT

   User of this library may want to return something and they will suprised
   if the library always set the response type to None.

===  Bug fixes

*  http: fix panic if Request.Form is not initialized on Endpoint.call

===  Enhancements

*  dns: add method to create Message from hostname and list of addresses

*  dns: add method to remove caches by names on Server

*  http: add method Put for Client

*  http: add method to convert RequestMethod to string

*  parser: add method to get single line

*  strings: add function to delete a value from slice of string