Security, compatibility and minor fixes

Fix: (http) fixes a security issue in the static file name resolution logic, where a maliciously encoded request could invoke an arbitrary response.

Fix: (fio, fiobj) improved C++ compatibility. Credit to Joey (@joeyhoek) for PR #76.

Fix: (fio) fixes an issue where timer cleanup wasn't performed after fio_stop (or SIGINT/SIGTERM). No a "clean slate" will be provided if fio_start is called more then once. Note: this may break previous behavior, which should be considered undocumented and unexpected behavior. (this fax may be deferred to version 0.8.x, still undecided). Credit to @fbrausse for opening issue #72.

Fix: (fio) fixes an issue where timer cleanup would be performed after the AT_EXIT state callbacks. Now the timer cleanup callbacks will be performed before the AT_EXIT callback (as they should). (See issue #72).

Fix: (fio) fixes signal handler (re)establishment test to prevent recursive signal calling.