start conversion to evented executor loop
use events; split out server loop; other small improvements; litter code with comments
Merge branch 'release-1.7' into develop
change some comments
remove an apparently unnecessary event from the server - it would block after p.start(), but so would the immediately following join, and slightly changed keyboard interrupt handling (but was apparently not introduced for that purpose); minor change to client shutdown routine
whoops
start working on resilience to client crash; not working yet
survive executor crash; other changes
forgot to clear event
stop launching executors if too many have failed
define client WAIT_TIMEOUT in only one place
remove a \t
fixes from code review
Merge branch 'evented_mainLoop' into survive_lost_executor

Conflicts:
	pydpiper/pipeline.py
	pydpiper/pipeline_executor.py
add heartbeat thread
small improvements
Merge pull request #118 from bcdarwin/survive_lost_executor

Survive lost executor
Merge branch 'master' of github.com:mfriedel/pydpiper into develop
* updated the logging setup, such that each executor writes its own logfile again. Pyro4 performs its own logging using the Python logging module. If not specified explicitly, all communication will be logged in the file "pyro.log". If you want this changed, you can either do that my setting environment variable (in or outside your program) or by setting the logging module parameter prior to importing Pyro4. Trying to change it after Pyro4 has been imported has no effect.
* also changed the format of the log filenames to make them slightly more human readable
* reverted the default memory allocation for pipeline_executors. Probably best set for in house computations (16G at MICe would not work well currently)