Expressions

- Support and documentation for rc.patterns, which enables/disables
  support for /pattern/ command line arguments.
- Support and documentation for rc.expressions, which enables/disables
  support for command line expressions.
- Now canonicalizes attribute names.
- Now canonicalizes modifier names.
- New colorization (temporary) that colors all Arguments::dump output
  green when processed.
- New distinction between 'old' and 'new' style command lines.  Old style
  is "pro:A +foo pri.not:M" with implicit "and" operators.  New style
  includes operators but does not include "+foo" and "/foo/".
- Many tokens are converted directly to primitive types (int, number,
  string) when no further processing is required.
- Restored CmdShow to functionality, and linearized the list of supported
  configuration variables, for easier insertion.
- Modified arguments.t.cpp unit tests.

src/Config.cpp

@@ -95,6 +95,8 @@ std::string Config::defaults =
   "burndown.bias=0.666                            # Weighted mean bias toward recent data\n"
   "regex=no                                       # Assume all search/filter strings are regexes\n"
   "xterm.title=no                                 # Sets xterm title for some commands\n"
+  "expressions=on                                 # Support for algebraic expressions\n"
+  "patterns=on                                    # Support for regex patterns\n"
   "\n"
   "# Dates\n"
   "dateformat=m/d/Y                               # Preferred input and display date format\n"