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.

doc/markdown/change_summary.md

@@ -13,7 +13,7 @@ Grbl v1.1's interface protocol has been tweaked in the attempt to make GUI devel
 
 - `< >` : Enclosed chevrons contains status report data.
 
-- `Grbl vX.Xx ['$' for help]` : Welcome message indicates initialization.
+- `Grbl X.Xx ['$' for help]` : Welcome message indicates initialization.
 
 - `ALARM:x` : Indicates an alarm has been thrown. Grbl is now in an alarm state.
 
@@ -72,7 +72,8 @@ On a final note, this interface tweak came about out of necessity, as more data
 
 - Buffer data (planner and serial RX) reports have been tweaked and combined.
 
-  - `Bf:0,0`. The first value is planner blocks in use and the second is RX bytes in use.
+  - `Bf:15,128`. The first value is the available blocks in the planner buffer and the second is available bytes in the serial RX buffer.
+  - Note that this is different than before, where it reported blocks/bytes "in-use", rather than "available". This change does not require a GUI to know how many blocks/bytes Grbl has been compiled with, which can be substantially different on a Grbl-Mega build.
 
 
 - Override reports are intermittent since they don't change often once set.