changes

Linmodem is soft modem source code for embedded system

* from version 0.2.4 to 0.2.5
=============================
- major rewrite, the API becomes stable.
- V8/V21/V23 should be usable.
- added X11 interface for the simulator. 
- better line model for the simulator: generic FIR filter. 
  Programmable echo generator (both neat & far end).
- V22 tx code (needed for V34 phase 2).
- V34: added adaptive equalizer, symbol timing recovery, phase
  recovery. Tests for fast training on the PP sequence (but not satisfactory).
- added AT parser.
- added serial protocol.
- added working soundcard hw support.

* from version 0.2.3 to 0.2.4
=============================

- major V90 update, the algebraic part is finished, and the CP packet
  parsing is done.
- added patches from Pavel (serial.c, lmreal.c)

* from version 0.2.2 to 0.2.3
=============================

- added V90 core, but no usable code yet.
- more patches from pavel for ltmodem.

* from version 0.2.1 to 0.2.2
=============================

- added extended V34 modulation for 31200 & 33600 speeds.
- added V34 negociation (not finished)
- added Pavel patches for ltmodem