This commit changes the function nsh_catfile() which underlies the 'cat' command and well as other NSH commands. Although this is the correct behavior for 'cat' it may not be the correct behavor for other commands implemented via nsh_catfile(). That remains to be determined.
include/ and netutils/: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
nshlib/: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
system/: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
testing/: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.
examples/: Remove references to CONFIG_DISABLE_SIGNALS. Signals can no longer be disabled.