adding some toString tests and refactoring parameterNode creation logic
Only test .js files in test/dialects

When enumerating dialect test files, the current algorithm attempts to
require() all files.  This is a problem for editors which create
swap/backup/temporary files and on systems where thumbnailers or other
system programs create files outside the control of the user.

Although we could attempt to exclude each of these files specifically,
or perform some exclusions based on hidden file names or attributes, it
seems easier to just limit the search to .js files, since that is the
only extension of interest currently.

Signed-off-by: Kevin Locke <klocke@quantpost.com>
MySQL does not do date UTCString, but ISOString format works
Merge pull request #107 from yc662/toStringDateObject

Date object toString using toUTCString, refactor duplicate code for ParameterNode, added a set of toString tests
Merge pull request #109 from kevinoid/for-upstream/test-js-only

Only test .js files in test/dialects
Split Unary into PrefixUnary and PostfixUnary

Separate unary nodes into separate prefix- and postfix- unary nodes in
preparation for adding prefix unary operators to the supported grammar.

Signed-off-by: Kevin Locke <klocke@quantpost.com>
Add support for EXISTS and NOT EXISTS expressions

Support checking the existence of subqueries using the SQL EXISTS and
NOT EXISTS expressions by adding `exists` and `notExists` methods to the
`Query` prototype.

This syntax is backwards compared to the SQL construction (which is
EXISTS [...] rather than [...] EXISTS) but seems more reasonable than a
putting `exists` in a shared scope.

Note that `notExists` could be implemented just as well with a unary
logical negation around the unary EXISTS, but since this is not done
elsewhere, it seemed preferable to stick with the existing style of
combining the negations with their positive counterparts.

Signed-off-by: Kevin Locke <klocke@quantpost.com>
Merge pull request #108 from kevinoid/for-upstream/prefix-operators

Support EXISTS and NOT EXISTS expressions
Bump version
allow multiple order() calls
Merge pull request #113 from sma/master

allow multiple calls to `order()` when constructing an `ORDER BY` clause

I'm gonna merge it and then make the minor refactor. Thanks!
refactor Query.order to fit the style of Query.select
refactor query.js
removing unnecessary code
Merge pull request #114 from yc662/cleanup

Unnecessary code in createIndex, dropIndex and indexes