Add summary of SLAP Format into README

README.md

+SlapOS Core
+===========
+
+The core of SlapOS - universal grid management tool based on *Python* and *Buildout*.
+
+Core components
+
+* SLAP Library
+* SLAP Grid
+* SLAP Format
+* SLAP Proxy
+
+Detailed documentation at <https://slaposcore.readthedocs.io/en/latest/>  
+Commercial deployment <https://slapos.vifib.com>  
+
+
+SLAP Format
+-----------
+
+Physically prepares computer according to `/etc/opt/slapos/slapos.cfg` and response from the *SlapOS Master*.
+
+Format creates *Partitions* inside `/srv/slapgrid/` with names `slappart<N>` and assign each partition to different user `slapuser<N>`. All users are part of the same group `slapsoft` so they can share some resources.

README.txt

-slapos.core
-===========
-
-The core of SlapOS.
-Contains the SLAP library, and the slapgrid, slapformat, slapproxy tools.
-For more information, see http://www.slapos.org.