add new pictures and Readme.md

UrumbotXYZ/fixed_z_axis_may_2022/README.md

+## Integrated XYZ machine with fixed short z-axis.
+
+Revised with wider x-beam and Kevlar string.   May 2022.  
+
+###  Assembly
+
+<img src=./img/y_bottom.jpg width=40%>
+
+<img src=./img/y_top.jpg width=40%>
+
+<img src=./img/xy_top.jpg.jpg width=40%>
+
+Add strings and the table:
+
+<img src=./img/xy_string.jpg width=40%>
+
+
+
+
+#### z-axis details.
+
+
+#### Some details
+
+ 
+### Results
+
+
+### Conclusions
+
+