yref: Fix compile

compiler, yatomic: Fix compiler checks

yref: Remove unneeded definition

README: Update yref.h

yref: Finish reference counting

yref: Delete circular reference check

WIP

yatomic: In single thread mode we don't need anything fancy here

Add yatomic.h

yskiplist.h: Allow users to plugin their own RNGs

yrnd.h: RNGs

exinc: Add uthash.h

Imported TinyCThread as ythread

Initial commit

Initial commit