SQL: add support for Oracle

Hi, I post this pull request on behalf of "RT" (cf. https://groups.google.com/forum/#!topic/f3-framework/UFDfw3uYnnM).

From the provided code, it looks like F3 should respect the following guidelines in order to work with Oracle databases:
* SQL queries should not end with a semicolon
* being a reserved keyword, *rows* should not be used as an alias in SELECT statements

There's also something with case sensitivity but I'm not sure to understand the implementation here. If "RT" comes here, maybe he can clarify it.

Here's what I found on [stackoverflow](http://stackoverflow.com/questions/7425153/reason-why-oracle-is-case-sensitive/7425931#7425931):
> By default, Oracle identifiers (table names, column names, etc.) are case-insensitive. You can make them case- sensitive by using quotes around them (eg: SELECT * FROM "My_Table" WHERE "my_field" = 1). SQL keywords (SELECT, WHERE, JOIN, etc.) are always case-insensitive.

> On the other hand, string comparisons are case-sensitive (eg: WHERE field='STRING' will only match columns where it's 'STRING') by default. You can make them case-insensitive by setting NLS_COMP and NLS_SORT to the appropriate values (eg: LINGUISTIC and BINARY_CI, respectively).