Fix seg fault on overloaded connection (CPP-167)

Improper static cast and use of pointer in timeout callback
Also removed unused parameter in Pool::maybe_notify_ready()
Add pool timeout test for CPP-167

RE: fix in commit 43c68da645afa030dd210a1f3816640ad96e2947

This required some core changes to make the driver start with zero
connections. I pursued this approach in order to make the test
deterministic (as opposed to really trying to overload a connection, or
messing with timeouts).
Guard against session close from session thread

Fixes CPP-161
,
Add NULL check to cass_value_get_*
Merge pull request #71 from datastax/CPP-167

Add pool timeout test for CPP-167
Merge pull request #72 from datastax/CPP-161

Guard against session close from session thread
Merge pull request #73 from datastax/CPP-165

Add NULL check to cass_value_get_*
Fixed Windows get_time_since_epoch() typo and added test
Merge pull request #76 from datastax/CPP-168

CPP-168
Merge branch '1.0' into beta5
Write batches w/o exposed settings