Add TBQueue, bump version to 2.4 and document changes since 2.3
drwxr-xr-x - Control
-rw-r--r-- 1611 LICENSE
-rw-r--r-- 87 Setup.hs
drwxr-xr-x - bench
-rw-r--r-- 77 prologue.txt
-rw-r--r-- 1223 stm.cabal
drwxr-xr-x - tests