vfs: no longer watch dirs when mounting - need to pass flag. allows
turning this off for screenshots dir (where hotloading doesn't make
sense)
vfs_tree: expand hash table when 3/4 full; 1/2 was quite wasteful.
main: do CPU init early, so timing during init can use TSCmain: do CPU
init early, so timing during init can use TSC
This was SVN commit r2098.