* Much better support for XPATH 1.0 according to https://www.w3.org/TR/xpath-10 using yacc/lex

* NOTE: Due to an error in the previous implementation, all XPATH calls on the form `x[a=str]` where `str` is a string (not a number or XML symbol), must be changed to: `x[a='str'] or x[a="str"]`
    * This includes all calls to `xpath_vec, xpath_first`, etc.
    * All calls to cli_copy_config in CLI spec files must replace 2nd argument from `x[%s=%s]` to `x[%s='%s']`
  * The old API is stillenabled. To define the new, define XPATH_USE_NEW in include/clixon_custom.h and recompile

lib/src/clixon_json.c

@@ -774,7 +774,7 @@ json_parse_file(int        fd,
 
 /*
  * Turn this on to get a json parse and pretty print test program
- * Usage: xpath
+ * Usage: json
  * read json from input
  * Example compile:
  gcc -g -o json -I. -I../clixon ./clixon_json.c -lclixon -lcligen