[Users] new feature: manage avp flags from script

[Daniel-Constantin Mierla]

Hello,

a new feature that allow to manage the AVP flags was committed in the 
development repository. Till now, the AVP flags were hidden to the 
configuration file, being available only inside the C code.

The AVP flags available to configuration file are 8bit long. They are 
not stored to database or radius, they are used only while the AVP last 
in memory. The main purpose of the flags is to be able to mark some AVPs 
for special processing or meaning.

One (very requested) example is to group avps per caller or callee. Same 
named AVP may be required to be loaded for both callee and caller. The 
previous option was to load one set, rename it and then load the second. 
Witht he new feature, one can load first set and mark it with a special 
flag and the second with another flag.

avp_db_load("$ruri","$avp(i1:123)"); # - callee's avps

avp_db_load("$ruri","$avp(i2:123)"); # - caller's avps

If the script flags are missing, then all avps are matched, regardless the script flags set (full compatibility with the old format).

All avpops functions were upgraded to handle the flags. Any feedback is appreciated, mainly the testing.

For more details, see the readme file of the avpops module.  

http://openser.org/docs/modules/1.1.x/avpops.html

Please pay attention that the avp naming format has changed, most of the 
functions' parameters being affected,. A new section in the readme has 
been introduced, read it carefully.

http://openser.org/docs/modules/1.1.x/avpops.html#AEN56

Cheers,
Daniel