fixed a potential test failure in a recently added test case in 025-codecache.t.
bugfix: ngx.exit(204) could try to send the response header for twice. nginx 1.5.4 caught this issue.
bugfix: the error message for failures in loading inlined Lua code was misleading.
bugfix: when a Lua line comment was used in the last line of the inlined Lua code chunk, a bogus Lua syntax error would be thrown.
minor refactoring in the closure factory.
minor cleanup in a recently added test case.
fixed test cases that tried to send the response header twice, which were caught by nginx 1.5.4.
Merge remote-tracking branch 'origin/master' into ffi