- Float type recognition is more robust, now handled using a regexp

- Date type recognition is more robust, now using a combination of regexp plus date object
- Parsing of strings representing dates is now cached, eliminating the need for double parse



git-svn-id: http://galileo.dmi.unict.it/svn/relational/trunk@270 014f5005-505e-4b48-8d0a-63407b615a7c

samples/ratings.csv

@@ -0,0 +1,9 @@
+id,rating
+0,5.3
+1,6
+2,5.7
+3,3.3
+4,9.1
+5,4.4
+6,5.1.1
+7,4.9