- make rcu try yielding when its buffer gets full, instead of throwing an assert
+ fix makefile to compute dependency info as a side-effect of compilation (-MF)
- investigate 16 byte CAS; ht can store GUIDs inline instead of pointers to actual keys 
- testing, testing, testing
+ support integer keys for ht
- validate arguments to interface functions
+ optimize tracing code, still too much overhead
+ use NULL instead of a sentinal node in skiplist and list
+ make the interfaces for all data structures consistent 
+ make list and skiplist use string keys
+ optimize integer keys
+ ht_print()
- iterators
- characterize performance of data structures
- experiment with the performance impact of not passing the hash between functions
- experiment with embedding keys in the list/skiplist nodes
- allow values of 0 to be inserted into maps (change DOES_NOT_EXIST to something else)