Improved code readability

Changed table echo to printf for more readable code
Wrapped sql_dump error message in __d(), as discussed here:
https://github.com/cakephp/cakephp/commit/4c4fdc6f70e5b98b043609af11025200d09263c6#commitcomment-3155723
and here:
https://github.com/cakephp/cakephp/pull/1491/files#r5646701
Merge pull request #1491 from ravage84/sql_dump

Improved code readability
Fix unlink() for CacheEngine::clear() failed on windows.
Fixing some errors related to unlink() on windows