API changes, most recent first:
+2014-02-xx - xxxxxxx - lswr 0.18.100 - swresample.h
+ Add swr_is_initialized() for checking whether a resample context is initialized.
+
2014-02-xx - xxxxxxx - lavr 1.2.0 - avresample.h
Add avresample_is_open() for checking whether a resample context is open.