S3 and debug packages have references to APEX functions (which prevents them from being installed independently)

[apeeterszeb]

What steps will reproduce the problem?
1. @install_amazon.sql in a database that does not have APEX installed
2. select * from dba_errors;
3.

What is the expected output? What do you see instead?
"amazon S3" only packages will not install unless APEX is present.

What version of the product are you using? On what operating system?
ORACLE 11.2.0.4 on RedHat linux

Please provide any additional information below.

There are a couple of references to APEX functions, which can likely be 
replaced with generic ones, so that S3 modules can be installed independently.

amazon_aws_s3_pkg.pkb:
  '&Signature=' || wwv_flow_utilities.url_encode2 (l_signature);

debug_pkg.pkb:
  if (apex_application.g_debug) then
    apex_application.debug (p_msg);
  ...
  if (m_debugging or apex_application.g_debug) then 

I just ran into the same problem that I found here: pellegrinimarcos/plsql-utils#26