format readme

README.md

@@ -1,16 +1,22 @@
 BUILD
 -----
+```shell
 cd ${HOME}
 R CMD build IEEE
 export LD_LIBRARY_PATH=/usr/lib/x86_64-linux-gnu:/opt/gurobi1200/linux64/lib
 R CMD INSTALL IEEE_1.0.0.tar.gz
+```
 
 TEST
 ----
-R
+From R do:
 --
-> library(IEEE)
-> compare(1,20,30,file="R-log.txt")
-
+```R
+library(IEEE)
+compare(1,20,30,file="R-log.txt")
+```
+with expected output:
+```shell
 $ cat R-log.txt
 1, 20, 30, 0.006, 0.357, "(!N&!P&!R) + (J&O&!S) + (B&!H&!Q) + (J&Q)", "(J&Q) + (!A&B&!O) + (F&O&!Q)", 3332, 233
+```