Usermode 0.6 is out

Main things added since version 0.5:
- 28 supported modems,
- support for some extra PPP encapsulations,
- configuration/compilation/installation scheme redesigned (see the INSTALL file),
- new config tool eciconftxt.sh (for console/terminal),
- documentation updated (README, INSTALL, TROUBLESHOOTING, online FAQ) and available in french and english,
- a lot of bug fixes

See the Changelog file for further detail)