Accept --no-config option to inhibit loading default config file, even without specifying another config
Probe erupter before icarus, since they are far more common now
configure: Remove duplicate sys/file.h check
Merge commit '7d7ea52' into bfgminer

Conflicts:
	configure.ac
Use git submodule for ccan (moving opt_*_floatval into miner.c)
make-release: Only include specific components of ccan
configure: Check for sys/termios.h used by ccan/opt
Load default config before commandline options, so the latter override the former (but prioritise defaultconfig pools last)
Merge branch 'upstream_ccan' into bfgminer
Merge branch 'default_config_first' into bfgminer