updated readme

README.md

-For more information about the C(anonical) Scan Matcher, see the webpage: http://purl.org/censi/2007/csm .
+This is a fork of the [C(anonical) Scan Matcher](https://github.com/AndreaCensi/csm).
 
-This is the "master" branch of CSM, which uses GSL.
+##Installation
 
-There is also another branch, called [``csm_eigen``][branch], which uses the ``eigen`` library. 
-This branch is the work of people working at U. Freiburg and Kuka, including
-Christoph Sprunk and Rainer Kuemmerle.
+Clone the repository in your chosen directory. In a terminal:
 
-[branch]: https://github.com/AndreaCensi/csm/tree/csm_eigen
-
-Binary install (via ROS)
-------------------------------
-
-(November 2015) Now you can install binary on Ubuntu (via ROS). As of today limited to Ubuntu Saucy and Trusty. To do so:
-
- 1. Add ROS repository to your Ubuntu's download site (For detail, see [ROS wiki](http://wiki.ros.org/indigo/Installation/Ubuntu)):
+```sh
+cd <your/path>
+git clone <repo-link>
+```
 
- ```
-sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list'
-sudo apt-key adv --keyserver hkp://pool.sks-keyservers.net --recv-key 0xB01FA116
-sudo apt-get update
+Create a directory to build all the source files:
+```sh
+mkdir build
+cd build
 ```
 
- 2. Install CSM. 
+Compile the source files. To change the install directory you must set cmake environment variable `${CMAKE_INSTALL_PREFIX}` (e.g. using command `ccmake ..` before calling `cmake ..`). 
+Its default value on UNIX-like/Linux systems is "/usr/local".
 
- ```
-sudo apt-get install ros-indigo-csm
+```sh
+cmake ..
+make
 ```
 
-The package name contains "ROS" specific info, but you can use this as a standalone CSM library. It goes into these directory:
+Finally, you can install the library (`sudo` is required only if `${CMAKE_INSTALL_PREFIX}` is a system diretory managed by administrator user root).
 
- ```
-/opt/ros/indigo/include/csm
-/opt/ros/indigo/lib/libcsm-static.a
-/opt/ros/indigo/lib/libcsm.so
+```sh
+make install
 ```
+