Created a NANODBC_STRLEN macro so that wide string lengths are properly computed in get_impl.
Reworked last_error to wide strings from SQLGetDiagRec, and convert them (crudely) to narrow strings for the exception message.
Changed the parameter number from "long" to "short" to reflect what SQLBindParameter, etc. expect to see.
fix various bugs on windows x64 unicode
* use of sizeof(str)/sizeof(NANODBC_SQLCHAR) for unicode string
* use '+ sizeof(NANODBC_SQLCHAR)' instead of '+1' for null terminated string
* SQLULEN is different than long on win64: change when calling SQLSetStmtAttr
* wcsftime from visual studio 2008 does not handle '%F' format
* SQLBindParameter:
  * when binding strings, the length of the string should be given as parameter instead of the length of the column in db.
  * Replace bind_parameter method with bind_parameter_string_array so that the length of each string in the array could be detected.
Merge branch 'duhlin_master' of https://github.com/duhlin/nanodbc into duhlin-duhlin_master
Getting things working on OS X.
merge