update p5-Device-Modem to 1.48.

changes since 1.36:

1.48  Sun Jun 24 09:30:16 CEST 2007
    - atsend() method made more reliable with longer commands (ex. longer
      sms messages).

1.47  Thu Apr 20 22:16:17 CET 2006
    - Sensible speedup in the command/response cycle.

1.46
1.45  Tue Nov 15 23:29:40 CET 2005
    - Fixed dial() now it does not wait for timeout in presence of a valid
      remote response (NO CARRIER, BUSY, ...)
    - Fine tuned answer read cycle times
    - Added constant $Device::Modem::WAITCMD for wait time before issuing
      commands (atsend)
    - Added patch to make Xmodem work from Aaron Mitti <amitti at 10east dot
      com>.
    - Now dial() accepts also '#' sign in numbers (thanks to Pierre Hilson).

1.44  Sat Apr 30 23:29:03 CET 2005
    - (again) now cygwin and darwin platforms should be detected correctly.
    - added a preliminary version of Device::Modem::UsRobotics module,
      that allows to access voice/fax messages stored on your UsRobotics
      message modem. Read the (incomplete) docs for more details.

1.42  Sun Sep 19 21:12:10 CET 2004
    - little fix for correct MacOSX os detection and SerialPort inclusion

1.39
1.38
1.37  Wed Aug 18 09:21:50 CET 2004
    - parse_answer() now in scalar context (string) returns *all* modem
      answer instead of removing the last string (OK/ERROR/...)
    - documented new example scripts: caller-id.pl and xmodem.pl

(grant)