moved code from header to source files

readme.md

@@ -149,18 +149,18 @@ tim_run (fps) -> bool
     The Ctrl-C interrupt is masked, so make sure to put an exit condition
     like this at the end of the main loop:
 
-        if (is_key_press(ESCAPE_KEY))
+        if (tim_is_key_press(ESCAPE_KEY))
             exit(0);
 
     fps     frames per second
 
-is_key_press (key) -> bool
+tim_is_key_press (key) -> bool
 
     Returns true if key was pressed.
 
     key     char literal or one of the KEY constants, see constants
 
-time_us () -> int64
+tim_time_usec () -> int64
 
     Returns monotonic clock value in microseconds. Not affected by summer
     time or leap seconds.