Define DEBUG when doing a Debug build
Add missing header inclusion to debug.h
Fix formatting: __LINE__ is a number, not a string
Add missing newline in debugging macro
Fix source file specific debugging macro
Add missing casts to void* to satisfy -Wformat
Add missing length modifier to format string
Added empty-check for linkedlist
Removed unused testcase variable
Ensure that the first element points nowhere after insertion
More extensive testing for the ll insertion and deletion

We actually should test if the data is in the linked list as well as
whether it was removed after we called the appropriate remove function.
Check if the linkedlist is actually empty after insertion and deletion of the elements
removed unused variable
Fix: Use only ll functions on test_ll_insert_data
Fix: Use only ll functions in test_ll_delete_data
Fix: Use only ll functions in test_ll_insert_multiple
Fix: Use only ll functions in test_ll_delete_by_predicate
Fix for older check versions with buggy ck_assert_int_eq()
Merge pull request #225 from neithernut/add-build-debug_flag

Add build debug flag
Fix: The CONSTPOW_TWO() macro should always be a size_t