Specifically, change the ptr_t typedefs for these LLCore classes to use
IntrusivePtr rather than directly using boost::intrusive_ptr. This allows us
to use a simple ptr_t(raw ptr) constructor rather than having to remember to
code ptr_t(raw ptr, false) everywhere. In fact, the latter form is now invalid:
remove the now-extraneous 'false' constructor parameters.

Initial version that should have enough of the plumbing to produce
a working adapter.  Memory test is showing 8 bytes held after one
of the tests so I'm going to revisit that later.  But basic
functionality is there going by the unit tests.

Beefed up the metrics gathering in http_texture_load to get memory sizes and
cpu consumption on windows (still need to implement that on Mac & linux).
Ran runs with various idle loops with sleeps from 20 ms down to pure spinning,
varied Block allocation size from 1504 to 2^20 bytes.  2ms/2ms/65540 appears
to be a good spot under the test conditions (Win7, danu grid, client in Boston).

Generally, opaque data operations are expected to be over 'void *' and have
now converted interfaces to do that.  Update() method honors millisecond limit to dwell
time.  Might want to homologate the millis/uSecs mix later....

chunking data.  Remove the stateful use of a seek pointer so
that shared read is possible (though maybe not interesting).

The unit/integration tests don't work yet as I'm still battling cmake/autobuild
as usual but first milestone passed.