Update README

Author: parasyte

README.md

@@ -8,17 +8,16 @@ Simple cross-platform runtime / startup (like crt0).
 
 ## Primary goals
 
-* Create a sane, platform-specific ABI environment
+* Create a sane, platform-specific runtime environment
   * Set the stack pointer
   * Clear the `.bss` and `.sbss` sections (uninitialized static data)
   * Minimal hardware initialization (e.g. configuring the FPU)
-  * Re-exports `F32Ext` and `F64Ext` traits from [`libm`](https://crates.io/crates/libm) (for platforms with an FPU)
+  * Panic handler
 
 ## Usage
 
-The `panic` function must be imported with `pub use`, or you will get missing-symbol errors at link time. The floating point trait extensions can also be used for convenience.
+The `panic` function must be imported with `pub use`, or you will get missing-symbol errors at link time.
 
 ```rust
 pub use rrt0::panic;
-use rrt0::{F32Ext, F64Ext};
 ```