Add string test for initialization
Add test for checking empty string length
Add test for catting empty strings and checking their length afterwards
Add preparation for empty multicat string test
Add test for empty duplication of string objects
Add test for empty string cmp()
Add test for getting empty string as raw
Add test for setting string from literal
Add test for setting string from buffer on heap
Add setup/teardown functions for more complex string testing
Add string ncmp test
Add substr testing
Add string cmp test
Fix unlocking order in ws_string_cmp
Comment out utf8-checks
Initialize error variable to indicate no error
Add missing NULL-checks
Return NULL if the string is, in fact, empty
Fix calloc call
Fix ws_string_set_from_raw()