TxtSushi 0.5.0

Hiya! I've uploaded TxtSushi 0.5.0 to hackage and there are quite a few changes. I still need to update the documentation on http://keithsheppard.name/txt-sushi which probably won't happen for a week or so (Edit: I have made the updates) but I'll summarize the changes here:

• generalized the JOIN syntax to allow joins on arbitrary expressions (you used to only be able to join on column IDs). This test script demonstrates a join on a simple expression
• added initial support for the "for x in [col1 .. col4] yield expr" syntax. See this test script for an example of how it works.
• parser now works with UNIX, DOS and Mac newlines no matter which OS you're working on
• added integrated help for all SQL functions and operators. Use "tssql -help" to get a list of all functions and operators. Use "tssql -help sum" to get help on the SUM function
• added many new function definitions
• Grouped data syntax generalization: you can now group tables multiple times (via nested selects) and join those grouped tables to other tables (grouped or not). You can even mix grouped and non-grouped columns in the same expression.
• Many bug fixes and code simplifications (still learning how to write good Haskell). Most notably it is now very easy to extend tssql with new SQL functions and operations. Here's an example of what it takes to add a new function.
• added support for bool constants in SQL expressions
• improved error messages
• Declared the "classic join" performance bug a feature :-)
• and most importantly: changed the synopsis to "The SQL link in your *NIX chain"

Have fun and please send me your bug reports!