+ 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/timestamp.h

@@ -32,5 +32,7 @@ typedef enum
     TIMESTAMP_END,
 } timestamp_t;
 
+#define TIME_STRING_SIZE_MAX 24
+
 char *timestamp_current_time(void);