refactor while we're at it

This is due to an issue with dmix where it will not release the device
after being closed.

simplify alsalayer xrun
split audio mainloop into smaller specific functions
simplify pulse audiostream
remove unused pulse functions

Move ALSA specific options to alsalayer only

inline error signaling in the one alsa function using them

Don't store a pointer to ManagerImpl
Store a reference to audio preferences
Remove unused noisesuppression state

we're using one unique mainbuffer instance inside managerimpl
remove use of setErrorMessage(-1)
simplify audiodriver creation

move some code from managerimpl code

Don't use a 8k buffer to format message, let v* functions do the work
Use yellow for warnings
Use either syslog either console output

Now it's created before accounts

fix a bug in account matching : when receiving a call sflphone would match it
with an account which had the local ip address as server even if the account was
deactivated