fix compile with option JABBER_EEPROM_SUPPORT
include jabber_ecmd.c in compile process if JABBER_EEPROM_SUPPORT is enabled
store settings in EEPROM
allow change of JABBER settinsg through ECMD and HTTP
solves http://bugs.ethersex.de/view.php?id=90
refs #247
refs #248
reduce data size by one to avoid out of bounds acces in debug macro JABDEBUG