add support for single-quoted strings, fix #270
introcude helper's name to helper options, fix #268
config methods on Handlebars must returns a Handlebars instance, fix #266
fix #259: Handlebars.Utils.isEmpty false positive for small big decimal
Jackson2 support: wrong output for array of strings, fix #260
set default locale in i18njs, fix #273
upgrade ANTLR to 4.2 (latest version)

See https://github.com/antlr/antlr4/releases/tag/4.2 fix #274