Fix dylib names on Darwin

As opposed to Linux (and other *nix), where is a common practice to append the library
version number as the latest extension, in OSX the convention is to put it
between the library name and the dylib extension.
Merge pull request #147 from planas/fix-dylib-names

Fix dylib names on Darwin
Clear compiler warning (loss of integer precision) on iOS
Merge pull request #148 from paulmelnikow/ios_compiler_warning

Clear compiler warning (loss of integer precision) on iOS
Fixed warnings.
Fixed warnings.
Added support of ttl parameter for keys.
Merge pull request #150 from madevgeny/master

Fixed warnings produced by gcc 4.7.2.
if we call mongo_cursor_next() for the first time and there is no result, we should return MONGO_CURSOR_EXHAUSTED
adding comment
Changed _get_host_port to allocate memory returned dynamically using bson_malloc rather than using static memory to make mongo_get_primary and mongo_get_host thread-safe
Merge pull request #152 from fotonauts/return_exhausted

if we call mongo_cursor_next() for the first time and there is no result, we should return MONGO_CURSOR_EXHAUSTED
Merge pull request #153 from Convey-Compliance/pull-thread-safe-_get_host_port

Made _get_host_port thread safe
aggregation examples from Charlie Page
doc type fix for Reading BSON objects - CDRIVER-237
0.8.1 release CDRIVER-234
0.8.1 release CDRIVER-234