Improve the calc build and release process

We apologize for the calc v2.14.0.12 source tarball that was missing
critical files.  While the executable was well tested, our release
process was deficient.

We are improved our release process and added tests during the release
procedure to help verify that we are not regressing in to the "v2.14.0.12
source tarball" issue, among other things.

Depending on how things do, you might is several releases come out over
a short period of time.  The core of calc isn't changing, so the calc
executable will be the same as we focus on the Makefiles, our release
procedure, and related documentation / help files.

We made several changes to the Makefiles.  We also added a new
README.RELEASE document (see "help release") that is a work in
progress. Along the way we discovered a few things that needed to be
updated in documentation.

See the CHANGES file for details.

Makefile.local

@@ -1 +1,18 @@
-# Add below to override Makefile values (using :=) as in: HAVE_STRING_H:= YES
+#
+# Makefile.local - local Makefile variables
+#
+# This file is included by Makefile after the last Makefile is set and
+# before the first make rule.  This makes this file suitable to override
+# Makefile variables.
+#
+# To replace a Makefile variale, use := symbols.  For example:
+#
+#	CCWERR:= -Werror
+#
+# NOTE: You need to remove the leading '#<whitespaces>' to take effect.
+# Comments start with a #-character.
+#
+# You can append to an existing Makefile variale using '+=' symbols.
+# For example:
+#
+#	CFLAGS+= -Ofast