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

+ 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
+ Simplified read_line to reduce cyclomatic complexity

+ renamed example files read.lua and read_line.lua
+ moved #define READ_LINE_SIZE to top of file
+ renamed g_linebuf to linebuf, and moved it into read_line as a static variable

src/tty.c

@@ -1615,6 +1615,7 @@ const char* get_serial_port_type(const char* port_name)
 
 const char* get_serial_port_type(const char* port_name)
 {
+    (void)port_name;
     return "";
 }