Fixed PHP-690: Percentage symbol is not escaped in error messages

We need to use "%s", error_message when passing to the varargs function
mongo_cursor_throw. The explanation for why this is important is well described
at http://en.wikipedia.org/wiki/Uncontrolled_format_string
Merged pull request #303

* pull-request/303:
  Fixed PHP-690: Percentage symbol is not escaped in error messages
Fixes PHP-680: Always free tagset in dtor function

Previously, tagset would not be freed if it contained no tags. Since it is always allocated, we should free it regardless of whether tags were added to it.
Merge pull request #304

* pull-request/304:
  Fixes PHP-680: Always free tagset in dtor function
Fixed PHP-691: Memory leak during master failover

MongoCollection->update() & remove() do not have this problem
Merged pull request #305
Fixed Windows build.
BUMP 1.3.4
Whitespace and CS fixing, phase 1.
Update after Hannes' review.
Merged pull request #307
Fixed PHP-437: Removed old API checks and some unused code.

We could remove some code as we don't support PHP 5.1 anymore.  I've tested to
build with 5.2.18, 5.3.22, 5.4.12 and 5.5.0 in both ZTS and normal builds at
64bit, as well as 5.3.20 and 5.4.9 in 32bit (no-ZTS).
Merged pull request #308