Add README to Rust Cleve-Moler Example

FPvsArbitraryPrecision/FP-ErrorEstimate-Rust/README.md

+# Overview
+
+This is a Rust Example of the Cleve-Molder precision estimate algorithm.
+
+
+# Requirements
+
+  - Rust
+  - Cargo
+  - `hyperfine`
+
+The `hyperfine` utility can be installed using cargo
+
+```
+cargo install hyperfine
+```
+
+# Compilation
+
+The code can be compiled in debug mode using
+
+```
+cargo build
+```
+
+or in release (optimized) mode using
+
+```
+cargo build --release
+```
+ 
+
+# Sample Execution & Output
+
+The standard `cargo run [--release]` command can by used to run the example.
+
+To run the program directly (i.e., without the overhead of Cargo) use
+
+```
+target/debug/fp-error-estimate
+```
+
+for debug mode or
+
+```
+target/relase/fp-error-estimate
+```
+
+for release (optimized) mode.
+
+
+## Abbreviated Sample Output
+
+```
+    1 -> 1.0
+    2 -> 5.0e-1
+    3 -> 2.5e-1
+    4 -> 1.25e-1
+    5 -> 6.25e-2
+    6 -> 3.12e-2
+    7 -> 1.562e-2
+    8 -> 7.812e-3
+    9 -> 3.906e-3
+   10 -> 1.9531e-3
+   11 -> 9.7656e-4
+   12 -> 4.8828e-4
+   13 -> 2.4414e-4
+   14 -> 1.22070e-4
+   15 -> 6.10352e-5
+   16 -> 3.05176e-5
+   17 -> 1.525879e-5
+   18 -> 7.629395e-6
+   19 -> 3.814697e-6
+   20 -> 1.9073486e-6
+```
+
+