Update "quick install" instructions in README.md

Author: mesheets

README.md

@@ -33,15 +33,11 @@ binary format).
 cd brickemu
 make
 export CROSSTOOLPREFIX=<path to h8300 cross-compiler toolchain (e.g. /usr/bin/h8300-hms- )>
-export BRICKOS_DIR=<path to brickOS home>
-export BRICKOS_LIBDIR=<path to brickOS lib dir>  (if not ${BRICKOS_DIR}/lib/brickos)
+export CROSSTOOLSUFFIX=<version or other suffix for the h8300 cross-compiler toolchain (e.g. -3 )>
 ./ir-server
-wish GUI.tcl -firm <path/to/brickOS.coff>
+wish GUI.tcl -rom <path/to/rom.srec> -firm <path/to/brickOS.coff>
 ```
 
-You can set BRICKEMU_DIR if you want to start emu from another
-directory.
-
 There are two possibilities to download firmware and programs.  The
 easy way is to choose "Firmware..." and "Load Program..." from the
 menu.  Make sure that the rcx is turned on before loading firmware,