Pyparsing 1.4 released

Thanks to all those who ran the beta version of 1.4 through its paces! During the beta we:
- caught the "warning" vs. "warnings" typo on the improved error-checking code
- beefed up the exception trapping when using regexp's
- added the new QuotedString class, for defining custom quoted string definitions

Thanks to all who took time to download and test the latest version of pyparsing!

-- Paul