Include dump address in the DUMP response
Rewrite the I/O with low-level functions

C streams still didn't behave well on sockets (e.g. sometimes a character
was swallowed).

Unfortunately, I also had to rewrite the getline() library call to achieve
it...
Reset lastcmd from conn_respond

Otherwise the wrong command may be mentioned in a bad response (e.g.
if you follow a command by an empty line).
Add makefile dependencies on header files
cleanup: Rename line.line -> line.data

The former looked a bit silly...
cleanup: Renumber GLS_xxx codes

The new scheme is easier to use. Basically, the more data is available,
the bigger is the numeric value of the corresponding GLS_xxx code, so
you can write code like:

    if (gls >= GLS_ONE)   /* if at least one complete line... */
Add functions to read raw data after a getline

It is not possible to use raw read on a FD that was used with getline,
because there may be additional buffered data, so we provide a custom
function for raw reads.
Use fdgetraw() instead of read() to read literals