Change signature of method startSSIDscan

The return value of method startSSIDscan has been used for two purposes; the number of networks (when executed successfully) and status reporting (return false). To better distinguish between (real) results and status information, the method's return type has been changed to bool. The original return value (number of networks) is now a reference parameter.

The type of the reference parameter has been changed to uint32_t according to field num_networks of ResultStruct_t.
Add optional CC3K debug printer to main class constructor.

This optional parameter allows a user to specify their own Print object for receiving debug output.  The default behavior of choosing hardware serial 1 is unchanged if the parameter is not specified.  This change follows the conventions of Arduino libraries and allows a user to use the hardware serial port without running into problems with the CC3K attempting to use it too.

This change was tested by running all the examples from the CC3000 test suite (here https://github.com/ladyada/CC3000_testing ) and verifying there were no regressions.  I also ran a version of the buildtest example which specified a null value for the printer and verified no debug output was written.
Remove SendTweet example because Twitter API now requires SSL and doesn't work anymore.
Remove tests subdirectory as tests have been moved to their own repo https://github.com/ladyada/CC3000_testing
Add data_types.h and merge type changes from updated host driver.
Merge small whitespace change in cc3000_common.cpp with new host driver.
Integrate new getmssvalue function into socket.cpp from new host driver.
Integrate wlan.cpp from latest host driver.
Integrate changes from new host driver.
Remove comment from security.h to match new host driver code.
Integrate changes to nvmem.h & nvmem.cpp from new host driver.
Change MIN_TIMER_VAL_SECONDS to 10 to match change in new host driver.
Integrate changes to evnt_handler.cpp from new host driver.
Bump host_driver_version.h version number to match new value in latest host driver.
Tweak whitespace to match new host driver.
Add reference to data_types.h to socket.h.
Update example code firmware check  to accept latest firmware version.
temporarily changing name to skirt an overload issue
inherit client, thus let Client objects tcp connect with connect
turn off some logging from more recent commits upstream