fbclient.dll from Firebird build should be included in the zip / installer

fbclient.dll from Firebird build (is in \bin dir) should be included
in the zip / installer

Bug reported by Jiri Cinkura

"Using fbclient.dll from Firebird’s installation and renaming it to
gds32.dll didn’t solve the issue.
 Surprisingly (thanks Process Monitor), the extension is looking for
fbclient.dll (in PHP’s directory, not in ext)."

Here is his blog post related to this issue there is No need to rename
it to gds32.dll (that is legacy how it worked in fb 1.x era)
http://blog.cincura.net/232299-my-pain-when-migrating-to-php-5-3-from-php-5-2-related-to-firebird-and-mysql/