[reSIProcate] resip::Condition

[Kenneth Ho]

Hi all,

I am working on some resip threading stuffs.
The wait functions in resip::Condition need a pointer to resip::Mutex 
(just like their PThreads counterparts). Since a Mutex is always 
required to call those functions, it would be more intuitive and 
rationale to just take a reference instead.
I added functions which take reference instead of pointer and modified 
other code in reSIProcate in accordance with them. The pointer version 
is not removed, therefore won't break other code those depend on 
resip::Condition.
However, I propose to deprecate the pointer version now and remove them 
some time later (before the next release?).

Cheers~

Ken Ho