Clean up errors and warnings in `BaseballCardList`
Refactor `BaseballCardDetails`
Fix errors in javadoc for `BaseballCardAdapter`
Fix warnings in `BaseballCardProvider`
Fix errors in javadoc for `SingleColumnCursorAdapter`
Add `final` specifier to constants, remove unused imports
Convert fields to local variables
Guard against possible NPE
Fix some warnings
Convert a field to a local variable
Fix error in javadoc
Merge pull request #263 from codeguru42/android/javadoc

Fixes: javadoc errors and lint warnings