* Work around for serial buffer over run
PronterFace sends a lot of M105 commands. During long operations such
as UBL's G29 P1, G29 P2, G29 P4 and G26 this can over run the serial
buffer. This results (very often) in a M1 (actually a M1M105) ending
up in the command queue.
Until we figure out a better way to resolve this issue, this will keep
the UBL commands from experiencing bogus commands at thier completion.
A number of regressions were patched also. The UBL G29 P2 and P4 Press and Hold had stopped working. It is very possible this is broken in the bugfix_v1.1.x branch also.
The main purpose of the Pull Request is to get the 3-Point mesh tilting to use the LSF algorithm just like the grid based mesh tilt. This simplifies the logic and reduces the code size some what. But the real reason to do it is the 3-Point case can be solved exactly. And by feeding these numbers into the LSF algorithm it provides a way to check all that code for 'correctness'.
G26 uses logic that looks like:
```
ex = _GET_MESH_X(i + 1) - (SIZE_OF_INTERSECTION_CIRCLES - (SIZE_OF_CROSSHAIRS));
```
The Bi-Linear macros need parenthesis to work correctly.
These changes may need to be warmed over. I tried to fix things with
the least amount of disruption. I just wanted to get the bugfix_v2.0.0
branch working for people again.
- Fix G26 Circle Drawing.
- Add default extrusion settings so machine can print lines on print bed
- Yet to be done: Get LCD Menu's to use these settings.
* Get UBL Mesh Generation, Mesh Save & Mesh Load working with 32-Bit platforms
* clean up read_data() and write_data() for non-LPC1768 HAL's
* Get read_data() and write_data() return codes consistent
All HAL's read_data() and write_data() return false if they succeed.
* Get read_data() and write_data() return codes to be consistent
Make read_data() and write_data() return true if an error happens.
* Say UBL is now checked out on machine types in default Configuration.h file.
