Update readme accordingly

slapos/README.format.txt

 format
 ======
 
-slapformat is an application to prepare SlapOS ready node (machine).
+slapformat is an application to prepare SlapOS-ready node to be used inside SlapGrid Cloud.
 
 It "formats" the machine by:
 
  - creating users and groups
  - creating bridge interface
  - creating needed tap interfaces
+ - creating TUN interfaces
  - creating needed directories with proper ownership and permissions
 
-In the end special report is generated and information are posted to
-configured SlapOS server.
+It reads configuration from /etc/opt/slapos/slapos.cfg and formats computer
+accordingly. The variables are number of partitions, IP addresses, storages
+and network interfaces.
+
+Format uploads a into configured SlapOS Master server.
+
+Format dumps allocated resources for the partition into a JSON file per 
+partition ~/.slapos-resource. This file contains network interfaces, 
+IP address ranges and port ranges. The resource constraints can be 
+recursively folded. 
 
 This program shall be only run by root.