updated docs to reflect recent changes.

bugfix: use of LuaJIT FFI when disabling the Lua code cache would lea…

…d to LuaJIT GC assertion failures like "g->gc.total == sizeof(GG_State)" because we unloaded the standard "ffi" module. thanks Ron Gomes for reporting this issue.

updated docs to reflect recent changes.

bugfix: a test case would fail when TEST_NGINX_PORT was set to port n…

…umbers other than 1985.

bumped version to 0.8.1.

bumped version to 0.8.0.

bumped version to 0.7.21.

updated docs to reflect recent changes.

bumped version to 0.7.19.

updated docs to reflect recent changes.