add some big improvements to parse error messages

change the parser to not attempt to parse the elements following
'from' unless there is a actual 'from'
improve the symbol parser to try to deal with issues when symbols are
  next to eachother with no intervening whitespaces
improve number literal parsing to fail if there are trailing letters
  or digits which aren't part of the number and aren't separated with
  whitespace
add some code to start analysing the quality of parse error messages

tools/Language/SQL/SimpleSQL/Tests.lhs

@@ -28,7 +28,7 @@ test data to the Test.Framework tests.
 > import Language.SQL.SimpleSQL.ValueExprs
 > import Language.SQL.SimpleSQL.Tpch
 
-
+> import Language.SQL.SimpleSQL.SQL2003
 
 Order the tests to start from the simplest first. This is also the
 order on the generated documentation.
@@ -44,6 +44,7 @@ order on the generated documentation.
 >     ,fullQueriesTests
 >     ,postgresTests
 >     ,tpchTests
+>     ,sql2003Tests
 >     ]
 
 > tests :: Test.Framework.Test