v1.1b: Tweaked Bf reports, jogging doc, saved another 160 bytes, minor bug fixes

- Increment to v1.1b due to status report tweak.

- Tweaked the buffer state status reports to show bytes and blocks
available, rather than in use. This does not require knowing the buffer
sizes beforehand. It’s implicit.

- Also, since buffer states are not used by most devs (after
inquiries), it is no longer enabled by default and a status mask option
was added for this.

- Fixed some typos and updated for the report tweak in the
documentation.

- Wrote a joystick implementation concept in the jogging markdown
document. Outlines how to get a low-latency feel to a joystick (and
other input devices).

- Removed XON/XOFF support. It’s not used by anyone because of its
inherent problems. Remains in older versions for reference.

- Added a compile option on how to handle the probe position during a
check mode.

- Fixed a jogging bug. If G93 is the modal state before a jogging
motion, the feed rate did not get calculated correctly. Fixed the issue.

- Refactored some code to save another 160+ bytes. Included an improved
float vector comparison macro and reducing a few large and repetitive
function calls.

- Fixed a probing bug (existing in v0.9 too) where the target positions
were not set correct and error handling was improper.

grbl/report.c

@@ -725,10 +725,12 @@ void report_realtime_status()
 
     // Returns planner and serial read buffer states.
     #ifdef REPORT_FIELD_BUFFER_STATE
-      printPgmString(PSTR("|Bf:"));
-      print_uint8_base10(plan_get_block_buffer_count());
-      serial_write(',');
-      print_uint8_base10(serial_get_rx_buffer_count());
+      if (bit_istrue(settings.status_report_mask,BITFLAG_RT_STATUS_BUFFER_STATE)) {
+        printPgmString(PSTR("|Bf:"));
+        print_uint8_base10(plan_get_block_buffer_available());
+        serial_write(',');
+        print_uint8_base10(serial_get_rx_buffer_available());
+      }
     #endif
 
     #ifdef USE_LINE_NUMBERS