Improved README

Author: schulzs

README

@@ -3,6 +3,19 @@ first-order logic. It is released as free software under the GNU GPL
 version 2, and without any warranty. See the file COPYING for
 details and the individual source headers for copyright information.
 
+Installation:
+=============
+
+Just clone the repository into a new directory, with e.g.
+git clone https://github.com/eprover/PyRes.git
+
+No futher installation should be necessary. If you are on a UNIX-like
+OS (including Linux or macOS/OS-X), and "python3" is not in your
+standard search path (or not Python 3), you may need to edit the
+#!-line at the beginning of the three main programs (see below),
+or in all modules if you want to run the unit tests.
+
+
 pyres-simple.py
 ===============
 
@@ -44,7 +57,11 @@ Suggested command line:
 ======== Information for CASC =================
 
 The system comes as a zip file in StarExec compatible format. It
-requires (any) Python3 as python3
+requires (any) Python3 as python3. The StarExec package can be
+regenerated by "make starexec". THIS WILL OVERWRITE
+$(HOME)/StarExec WITHOUT FURTHER WARNING. You can change the build
+path in the Makefile.
+
 
 The runscript is starexec_run_PyRes_default