Version 1.8 (#280)

* Version bump

* Update README

* Apply suggestions from code review

Co-Authored-By: Philip Top <top1@llnl.gov>

* Adding mark for deprecated items

LICENSE

-CLI11 1.7 Copyright (c) 2017-2019 University of Cincinnati, developed by Henry
+CLI11 1.8 Copyright (c) 2017-2019 University of Cincinnati, developed by Henry
 Schreiner under NSF AWARD 1414736. All rights reserved.
 
 Redistribution and use in source and binary forms of CLI11, with or without

include/CLI/Version.hpp

@@ -6,8 +6,8 @@
 // [CLI11:verbatim]
 
 #define CLI11_VERSION_MAJOR 1
-#define CLI11_VERSION_MINOR 7
-#define CLI11_VERSION_PATCH 1
-#define CLI11_VERSION "1.7.1"
+#define CLI11_VERSION_MINOR 8
+#define CLI11_VERSION_PATCH 0
+#define CLI11_VERSION "1.8.0"
 
 // [CLI11:verbatim]