Output library resolution details only at higher verbosity

This increase backward compatibility with arduino_builder

Author: cmaglie

legacy/builder/resolve_library.go

@@ -40,12 +40,15 @@ import (
 func ResolveLibrary(ctx *types.Context, header string) *libraries.Library {
 	resolver := ctx.LibrariesResolver
 	importedLibraries := ctx.ImportedLibraries
-	logger := ctx.GetLogger()
 
 	candidates := resolver.AlternativesFor(header)
-	logger.Println(constants.LOG_LEVEL_INFO, fmt.Sprintf("Alternatives for %s: %s", header, candidates))
-	logger.Println(constants.LOG_LEVEL_INFO, fmt.Sprintf("ResolveLibrary(%s)", header))
-	logger.Println(constants.LOG_LEVEL_INFO, fmt.Sprintf("  -> candidates: %s", candidates))
+
+	logger := ctx.GetLogger()
+	if ctx.Verbose {
+		logger.Println(constants.LOG_LEVEL_INFO, fmt.Sprintf("Alternatives for %s: %s", header, candidates))
+		logger.Println(constants.LOG_LEVEL_INFO, fmt.Sprintf("ResolveLibrary(%s)", header))
+		logger.Println(constants.LOG_LEVEL_INFO, fmt.Sprintf("  -> candidates: %s", candidates))
+	}
 
 	if candidates == nil || len(candidates) == 0 {
 		return nil