Output assumes that char is unsigned

[saolaolsson]

Output of deconz-cli-plugin on Debian/x86 (defaults to signed chars):
<-LQI 0x0000 02 0 2 0x0000000000000000 0xE7AB 1 1 2 01 01 FFFFFFF6

Output of deconz-cli-plugin on Debian/x86 compiled with -funsigned-char:
<-LQI 0x0000 02 0 2 0x0000000000000000 0xE7AB 1 1 2 01 01 F6