radius: implemented mppe support
various improvements and bug fixes

lcp: Ident

Merge branch 'accel-pptpd' of ssh://accel-pptp.git.sourceforge.net/gitroot/accel-pptp/accel-pptp into accel-pptpd

radius: implemented extension Acct-Input-Gigawords, Acct-Output-Gigawords
lcp:    implemented maximum/minimum mtu/mru checks

log: simplified engine
various bug fixes

        and newly introduced -  ip-change, when radius CoA request received,
        also this module manages pppd compatible radattr.pppX files
core:   implemented module 'sigchld' which handles SIGCHLD signal,
        waits child processes to terminate and manages pid terminate handlers

radius: upgraded dictionary to support vendor-specific

lcp: fixed incorrect echo reply
ppp_fsm: fixed incorrect timeout timer initialization

log: implemented log_file logging target with per-user/per-session support

         It will check that ip address of tunnel is not in range of clients ip addresses.
         This will avoid kernel softlockups due to loopback occured.