fix typo in Makefile example
Don't strip debug symbols of elf to use as symbol-file in gdb (fix crashing
gdb 7.7.1 on Ubuntu). Add debug-eclipse target and use target-specific CFLAGS
for debug targets.
adjust qemu commandline to enable serial communication with telnet
extent uart driver with stubs for additional interrupts and also look for
qemu's pci-serial-2x and pci-serial-4x devices