don't allow native methods to be called during spec runs.
make sure parameters are upper case strings before calling native code. add specs.
more specs.
specin'
monkey patch read_size_t and write_size_t into FFI::MemoryPointer
rip out compat; need to re-implement later
wrap data threshold get/set (closes #19)
add cursor support (closes #18)
documentation for cursor methods.
breaking change: wait() now returns nil instead of :nop