dirstate: refactor granularity code, add a test - rename option dirstate.granularity - move option reading into .write() - add a simple test

dirstate: ignore stat data for files that were updated too recently This should fix the race where hg commit foo <change foo without changing its size> happens in the same second and status is fooled into thinking foo is clean. A configuration item is used to determine the timeout, since different filesystems may have different requirements (I think VFAT needs 3s, while most Unix filesystems are fine with 1s).

pager: remove pager code from core