README: updated build instructions, prerequisites

README.md

@@ -1,6 +1,6 @@
 # ECL
 
-#### Very lightweight Estimation & Control Library.
+**Very lightweight Estimation & Control Library.**
 
 [![Build Status](https://travis-ci.org/PX4/ecl.svg?branch=master)](https://travis-ci.org/PX4/ecl)
 
@@ -8,11 +8,35 @@ This library solves the estimation & control problems of a number of robots and
 
 The library is currently BSD licensed, but might move to Apache 2.0.
 ## Building EKF Library
-Prerequisite:
+
+### Prerequisites:
+
   * Eigen3: http://eigen.tuxfamily.org/index.php installed
 
+#### Ubuntu:
+
+```
+sudo apt-get install libeigen3-dev
+```
+
+#### Mac
+
+```
+brew install eigen
+```
+
+
 By following the steps mentioned below you can create a shared library which can be included in projects using `-l` flag of gcc:
-  * mkdir Build/
-  * cd Build/
-  * cmake ../EKF
-  * make
+
+```
+mkdir Build/
+cd Build/
+cmake ../EKF
+make
+```
+
+Alternatively, just run:
+
+```
+./build.sh
+```