mode: Split MODE_UNSET_ONLY into MODE_NO_RESET and MODE_NO_SET
mode: Add MODE_FORCE_ALL flag, allowing access checks to be bypassed
user: Create umode infotab and context
user: Resetting umode bits should use &= ~, not |=
mode: Add simple buffered mode stacker
core/mode: Implement user /MODE
core/euid: Process user mode parameter
core/sjoin: Use new modes API
chan: Implement +l, +k, and +f
core/sjoin: Clear modes in ts_lose more cleanly
mode: Clear stupid logging lines