Feature Request: Display errors inline instead of appending them at the bottom

[tkopets]

Issue Type: Feature Request Version: v0.9.0 OS: Windows, MacOS RDBMS: All

Description

It would be best to combine stderr and stdout, so the output contains errors in place, where they happened instead of appending them at the end of the output. If multiple queries are executed this will allow users more easily spot which statement caused error(s).

Steps to show how this can be helpfull

1. Configure connections
2. Select connection
3. Execute multiple SQL statements and one of them should display error. E.g.:

   select 'a';
   select non_existing_identifier_to_get_error;
   select 'z';

Current SQLTools output:

 ?column? 
----------
 a

 ?column? 
----------
 z

ERROR:  column "non_existing_identifier_to_get_error" does not exist
LINE 1: select non_existing_identifier_to_get_error;
               ^

Suggested SQLTools output:

 ?column? 
----------
 a

ERROR:  column "non_existing_identifier_to_get_error" does not exist
LINE 1: select non_existing_identifier_to_get_error;
               ^
 ?column? 
----------
 z

The difference is that error is displayed in more appropriate place (in order where it actually occurred).

[tkopets]

Will work on this as this is closely related to #91