Improved warnings on failure to connect

Adding a warning (with the error message) when can't connect to a host.
And adding the host name into the error message when failed.

Closes #91
abi additions and small cleanup
making public DEFAULT_SOCKET_TIMEOUT_MSEC and changing the name to match MONGOC_DEFAULT_CONNECTTIMEOUTMS

Closes #95
Fix error while compile using vs10 on windows:
mongoc-database.c(687): error C2275: 'bson_string_t' : illegal use of this type as an expression

Closes #117
Fix link error while compiling using vs10 on windows without openssl:
error LNK2001: unresolved external symbol mongoc_rand_add	libmongoc.def

Closes #119
Missing entry call

Was interesting seeing tracing leaving a function it didn't enter

Closes #123
CDRIVER-486: There is no need to depend on sasl for PLAIN authentication

Closes #140
CDRIVER-485: Invalid read on authentication failure

Closes #141
CDRIVER-487: Missing entry calls

Closes #142
add wrap function 'mongoc_stream_write'.

Closes #130