bugfix pluginPaths configuration missing in 1.3

again, i see the pluginPaths configuration is missing, and this time I've fixed it by defining a reasonable default array instead of an empty array.
went ahead and assigned to a configuration so we are not re-defaulting for multiple requests.

related to previous commit 5661f98e3ea4eb991ffcd615bcc46c46a46f8932
https://github.com/CakeDC/migrations/commit/5661f98e3ea4eb991ffcd615bcc46c46a46f8932
Fixing Test. Adding migrations directory to test_app
Fixing edge case of changing from a string to an integer field type
Fixing schema comparison, using $newTables variable to check if any table were deleted.
Adding a check for empty type, to avoid an error message
Adding gitignore entries. Fixing pluginPaths to include plugins outside app directory
Merge remote-tracking branch 'upstream/1.3' into 1.3

Conflicts:
	vendors/shells/migration.php