Merge pull request #17 from seanwolter/master

improved performance of bulk imports and improved debug only logs and asserts
removed redundant #ifdef DEBUG around asserts because the compiler already strips asserts by default in production builds
fixed STAssert in place of NSAssert
Merge pull request #18 from seanwolter/master

fixed redundant ifdef DEBUG and STAssert instead of NSAssert
fixed stupid assert that was wrong
Merge branch 'master' of github.com:vokalinteractive/CoreDataManager-iOS
Fixed typo in fetchLimit init. Changed DLog to CDLog which is now activated by DEBUG_DATA