[RPL/2] RPL/2 4.0.6

[BERTRAND Joel]

	Hello,

	New minor release with some fixes:

- pipe() is overwritten by a macro to avoid a system error. 
Communication between process are done with pipes and these pipes are 
managed by a specific asynchrone thread. If a script try to create more 
threads than management thread can destroy, you can quickly achieve 
maximum number of opened files and pipe() shall return a system error. 
This macro tries to create pipes. If pipe() function returns an error, 
macro waits and retries. If number of retries is greater than a 
hardcoded value, macro returns an error;
- major bug (deadlock) is fixed in process and thread management. I hope
this bug shall be the last one;
- major bug is fixed in DET intrinsic (determinant was computed without 
LU diagonalization);
- SWAPCNTXT is added;
- minor bug is fixed in Makefile.am (licences rule).

	Regards,

	JKB