update README (#669)

Author: rahulk29

README.md

@@ -8,7 +8,6 @@
 
 ## Installation/Usage
 
-Substrate is a library, and cannot be run by itself.
 To use Substrate, [install Rust](https://www.rust-lang.org/tools/install),
 and add `substrate` as a dependency in your project's Cargo.toml:
 
@@ -46,14 +45,6 @@ just test
 
 from the root of the Substrate repository.
 
-Most tests for Substrate can be found in `substrate/src/tests`. These include a mix of unit tests
-and integration tests, but may break the abstraction barrier as they a part of the `substrate` crate.
-
-Substrate integration tests can be found in the `tests` crate.
-These tests double as examples of how to use Substrate.
-If you wish to see the artifacts generated by an integration test,
-look in the appropriate folder in `tests/build`.
-
 ## Contributing
 
 If you'd like to contribute to Substrate, please let us know. You can: