accept 1st argument: working directory

since [writesf~] writes to the directory of the abstraction
(rather than the patch, or the PWD), we have to manually provide the PWD
via an argument.
add PWD to the argument of loaded patches

PWD is received through "_MINT_pwd"
(and falls back to ".")
move private methods to the beginning of class
getPort(): getter for listening-port

so we can find out programmatically, on which port the server is listening
allow registering catchall callbacks

is a general oscPrefix is defined (in the constructor), we try to
register a subtree match (trailing '/') - this is not implemented on the sender-side yet!
handle empty (None) oscPrefix
restarting Pd-server
[connect( message should go to [udpclient]

and not to [unpackOSC]
no use to disconnect [udpclient]

disconnecting a non-connected client gives an error.
and [udpclient] seems to be able to cancel existing "connections",
whenever a new "connect" comes in.
reconnect on timeout
make doneCb private

renamed it to "_doneCb"
don't autostart Pd-process

so we can add callbacks before Pd get's launched
debug OSC-input

print OSCin messages (on demand)
added start/add/send message to pdserver
handle None-data as empty array
simple example for using PdServer

it receives "/meter" messages and replies with a "/pong"
added CWD and CPD support to Pd-server

CWD: working directory
CPD: patch directory
check for None before shutting down
start DSP after 1sek
patch-directory is not the same as MINT-patchdir

patch-directory is user-defined!

USERpatchdir: where users uploaded their patches to
MINTpatchdir: where we find the infrastructure

MINTpatchdir is calculated on the fly from the position of the
pdserver.py file.
USERpatchdir: MINTsm should know...