path params - allow underscores in path param names

This fixes #170

restx-core/src/main/java/restx/StdRestxRequestMatcher.java

@@ -112,6 +112,11 @@ void parse() {
        void end(PathPatternParser pathPatternParser);
    }

    private static boolean isValidPathParamNameChar(int curChar) {
        //only letters/digit/underscore are authorized in path param name
        return Character.isLetterOrDigit(curChar) || curChar == '_';
    }

    private static final class CurlyBracesPathParamPathParserCharProcessor implements PathParserCharProcessor {
        private int openBr = 1;
        private boolean inRegexDef;
@@ -166,8 +171,8 @@ public void handle(int curChar, PathPatternParser pathPatternParser) {
                    inRegexDef = true;
                    pathParamRegex.append("(");
                } else {
                    if (!Character.isLetterOrDigit(curChar)) {
                        //only letters are authorized in path param name
                    if (!isValidPathParamNameChar(curChar)) {
                        //only letters/digit/underscore are authorized in path param name
                        throw new IllegalArgumentException(String.format(
                                "illegal path parameter definition '%s' at offset %d" +
                                        " - only letters and digits are authorized in path param name",
@@ -188,7 +193,7 @@ public void end(PathPatternParser pathPatternParser) {
        private StringBuilder pathParamName = new StringBuilder();
        @Override
        public void handle(int curChar, PathPatternParser pathPatternParser) {
            if (!Character.isLetterOrDigit(curChar)) {
            if (!isValidPathParamNameChar(curChar)) {
                pathPatternParser.patternBuilder.append("([^\\/]+)");
                pathPatternParser.stdPathPatternBuilder.append("{").append(pathParamName).append("}");
                pathPatternParser.groupNamesBuilder.add(pathParamName.toString());

restx-samplest/src/main/java/samplest/core/ParametersResource.java

@@ -46,9 +46,9 @@ public void setVal(String val) {
        }
    }

    @GET("/params/path/{a}/:b/{c:\\d+}:d")
    public String pathparams(String a, String b, String c, String d) {
        return "a=" + a + " b=" + b + " c=" + c + " d=" + d;
    @GET("/params/path/{a}/:_b/{c:\\d+}:d")
    public String pathparams(String a, String _b, String c, String d) {
        return "a=" + a + " b=" + _b + " c=" + c + " d=" + d;
    }

    @GET("/params/query/withOptionalString")