ODBC32: preliminary Unicode implementation of ODBC functions

[Alex Villaci­s Lasso]

This started because I wanted to run an application which uses ActiveX 
Data Objects (ADO) under Wine, and I did not want to use the native ODBC 
manager, but the builtin one. I then discovered that ADO relies almost 
exclusively on Unicode calls to ODBC, which are currently unimplemented 
in Wine. So, I spent a weekend writing ODBC proxies for the Unicode 
functions. This was greatly aided by the fact that UnixODBC already 
provides Unicode versions of its exported functions, so all I had to do 
(in theory) was to load them in the same way as the ANSI versions. It 
seems that iODBC also provides Unicode versions of these functions 
(untested).

However, there are a few notes about this implementation:
* Some functions have to "cheat" in order to allow ADO to run normally. 
By "cheat", I mean to report success to ADO even when the function 
actually failed. ADO seems to be picky on the SQLSetStmtAttrW function, 
and throws an exception when it is reported that the attributes 
SQL_ROWSET_SIZE or SQL_ATTR_ROW_ARRAY_SIZE failed to be set. However, it 
seems that ADO still runs correctly when lied about these two attributes 
alone.
* Another issue is that of translation on the functions 
SQLColAttributesW and SQLColAttributeW. When a string attribute is 
requested on a column, UnixODBC returns a *character* count. However, 
the Windows ODBC returns a *byte* count, and ADO so expects it. Ignoring 
this issue results in corrupted column names in ADO. So the proxy checks 
for the byte/character distinction for known string attributes, and 
recalculates the byte length as necessary. There could be more functions 
which require this translation, but SQLColAttribute(s)W was the absolute 
minimum required for ADO.

This implementation allows any ADO application which uses a DSN for 
connecting to have a chance of working with the builtin ODBC proxy. 
Applications which use DSN-less connection strings are (still) out of 
luck, because this requires low-level ODBC support which is (currently) 
not present in UnixODBC.

All tests performed against a Linux MySQL database using the Linux 
MyODBC 3.51 driver.

Changelog
* Implemented Unicode proxy for ODBC

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