+ Add system timestamps to lua read() and new lua read_line() per global options; prevented warnings

+ Add missing timestamp-format epoch; update send_ to use fsync and tcdrain like normal tty_sync does; rework read_line to save partial line at timeout

examples/lua/lines.lua

@@ -0,0 +1,17 @@
+read(1000, 8000) -- read initial config
+send("\n")
+read(650, 100) -- main menu
+send("S") -- S menu
+n = 1
+while n > 0 do -- while not empty, read more
+  n, str = read_line(25)
+end
+while true do
+  send("t") -- query PV table
+  msleep(880)
+  n = 1
+  while n > 0 do -- while not empty, read more
+    n, str = read_line(60)
+    msleep(60)
+  end
+end