Fixes errors in ArraySource tests.

Since CakePHP 2.3 the test was throwing errors due to a change in
the core. The change was related to the order clause of the query.

Previously CakePHP passed the order clause as an array of compiled
strings. Since 2.3 CakePHP passes multidimensional arrays when
they are defined as such in the original query.

This core change caused implode() to throw errors because it can't
handle multidimensional arrays.
Fixes logging based on debug value.
Makes the ADOdb source PHP 5 ready.

- Fixes strict errors.
- Adds visibility keywords.
- Updates docblocks.
Fixes XmlrpcSource tests.

Google gave redirects instead of XML output. It causes the test to
fail, because it used to output XML. This commit switches the feed
to something that does return XML.
Actually tests AmazonAssociatesSource::_signQuery().

The test was throwing an error. It tried to access a log item that
didn't exist, because the method that was supposed to fill the log
was mocked.
Merge pull request #54 from Phally/2.3-tests

Failing tests on CakePHP 2.3 & 2.4