3.0.x - radeapclient - parallel mode (and more stuff)

- Added a "rce_request_t" structure which allows to store a request
context.
- Load all requests from files (or stdin) in memory in a list of
"rce_request_t".
- Use packet list and socket functions provided by FreeRADIUS library.
- Added support for "parallel" (option -p) and "send rate" (option -n).
- Added a "receive/send" loop, sends requests in parallel mode (similar
to radclient).
- Added statistics (option -s).
- Better handling of output according to debug/quiet (options -x and
-q). No more wilds printf's.
- Bug fix in EAP-SIM client state machine (error case).
- Updated attribute handling as from latest radclient code.