Update README.md

Author: mdimura

README.md

@@ -1,6 +1,6 @@
 Sparsehc-dm is a python wrapper for sparcehc distance matrix clustering algorithm, integrated with STXXL[![DOI for Citing STXXL](https://img.shields.io/badge/DOI-10.1002%2Fspe.v38%3A6-blue.svg)](http://dx.doi.org/10.1002/spe.v38:6) for on-disk sorting. SparseHC [![DOI for Citing SparseHC](https://img.shields.io/badge/DOI-10.1016%2Fj.procs.2014.05.001-blue.svg)](http://dx.doi.org/10.1016/j.procs.2014.05.001) is a memory-efficient hierarchical agglomerative clustering implementation. It has close to linear memory complexity, enabling clustering of ~900000 structures/points on 32GB RAM.
 
-Usage example:
+#### Usage example:
 ```python
 import mdtraj as md
 from sparsehc_dm import sparsehc_dm
@@ -19,12 +19,12 @@ for i in range(0,Nframes-1):
 
 Z=sparsehc_dm.linkage(m,"complete")
 ```
-###Instalation
-####Prerequisites: boost graph and stxxl library
+### Instalation
+#### Prerequisites: boost graph and stxxl library
 ```
 sudo apt-get install libboost-graph-dev libstxxl-dev libstxxl1
 ```
-####Building:
+#### Building:
 ```
 git clone https://github.com/Burning-Daylight/sparsehc-dm.git sparsehc-dm
 cd sparsehc-dm
@@ -33,4 +33,4 @@ cd build
 cmake ..
 make
 sudo make install
-```
+```