1. Warnings removed from mongo.c. 2. problem with conn_->primary->host not initialized properly implemented. 3. Added full support to compile properly with Visual Studio in 64bits. 4. Added support to integrate chunk compression/encryption on GridFS. 5. A

This commit contained removal of several warnings on Mongo.c under Visual Studio 2010 and also solves the problem of conn_->primary->host not properly initialized the right way.
The current code as reported on Jira, doesn't solve the problem because doesn't check the state of the first character of the string but rather the value of the pointer
Other main thing done is to add proper support for 64 bits compilations. There were specific variables that should have been declared to hold 64 bits values (like socket handle) and many explicit casts were needed