-{d,M}[module[,=args...]], remove potion_cmd_compile

add -M module loader and -d debug module loader, with initialization code
remove unneeded potion_cmd_compile, do all in potion_cmd_exec

-dremote initializes the debug/remote socket for ZeroBraneStudio
-dz loads the GUI (debug/z)
new debug op with ast, load debug.pn

improve debug framework, load debug modules (default or remote so far)
add debug ops for each new line in the src, pointing to the ast (in f->debugs)
remove unneeded potion_cmd_compile
turned off new DEBUG_IN_C, handle the debug loop in src
starting the loop is still broken, i.e. compilation of the ast for debug loop(src,proto)
tuple_bsearch returns now false if element not found, not -1
allow method be named loop

before loop was like a keyword, taking no 1st arg and block as 2nd
this fixes loading the debugger loop
I like a method named loop for every event loop
debug: disable src debugger for now

fix getting ast from f->debugs, but the debugs are not kept on the stack
(no step-into possible yet)
eval does not use the current environment yet
debug: add debug classes (unfinished)
fib.pn: different lines for -d
more nbody.pl fixes