Avoid unnecessary use of length/1
Remove short trace info from trace states
Simplify detection of messages sent to processes after they have exited
Update trace information with data from latest run

This fixes the ets_ref_keys test and.
Merge branch 'simplifications'
Fix bug in dependency relation
Fix minor compilation warnings in dpor suite tests
Add one more test in the dpor suite
Create functions for debugging purposes

Add `debug_print/1', `debug_print/2', `debug_apply/3'
functions that can be called inside instrumented code.
Fix a dialyzer warning
Delete temp files right after instrumentation
Support `crash' flag in testsuite

Add support for a crash flag in testsuite.
When a test has this flag it means we
expect it to crash (not just fail).
Crashing when a process takes too long to respond

Crashing and reporting when a process takes
too long to respond by Stavros Aronis
Add --wait-messages flag

Concuerror will wait for messages from
uninstrumented processes to arrive.
This slows down Concuerror (in some cases
using this option can make a big difference
in time) so I have disable it by default.

Still there are applications that crash
with or without using this flag so we
need to find a better way to wait for
this kind of messages.
Add some more interesting tests to DPOR suite
Remove support for multiple predecessors in backtrack sets
Add more tests to dpor suite
Don't rename concuerror_* modules
Don't allow unregistered process to run instrumented code

Crash Concuerror when an unregistered processes
is trying to run instrumented code.
Remove a debug message I forgot