fix warnings and removed some asserts

* removed lastAttemptedSubTree variable in octree server since we aren't using it.
* changed a bunch of asserts to debug messages since they produce warnings on unix and because the warning messages are a more graceful failure.
* fixed ByteCountCoded<> which was using T when it should have used int
* fixed lots of signed/unsigned warnings through the code
* fixed a couple of floats not properly defined warnings on windows
* fixed an uninitialized variable warning in MetavoxelSystem.cpp
* fixed a couple of truncated values warnings
* fixed an accidental bool that should have been an int in PropertyFlags<Enum>:
@chansensturm - can you double check that this is reasonable? This was happening implicitly anyway, so I just added the explicit cast to silence this warning:

```
/mnt/ebs1/jenkins/jobs/hifi-pull-request-ubuntu/workspace/libraries/audio/src/AudioSourceNoise.h:51:9: warning: large integer implicitly truncated to unsigned type [-Woverflow]
```