While dynamic linking works on linux & Mac OS due to rpath support 
Windows can't find the dll when debugging the test case unless it's 
copied into the tests builddir or it has it's working dir set to the 
DLL's builddir.

Also prevent compiler complaining about inconistent dllimport/dllexport 
linkage by ensuring KM_KBP_EXPORTING is defined on Windows too.

Make it clear the $id needs to be changed.

Check context_items_to_utf16 doesn't overrun it's buffer.
Add tests for context_clear, context_shirnk and context_append.
Add test including marker type context item.

Need to correctly terminate the context_item presentation form array.
Also refactor the method onto the km_kbp_context adadaptor class where 
it belongs.

It can do allocation when prepending. Catch exception and turn into a 
status code.

Covers everything except appending and shrinking.

It did not read the input string due an error in 
utfcodec:_utf_sentinal_iterator and did not include the null terminator 
in calculated size from context_to_utf16.

Also fix up a number of types in fucntion names and the KM_API macros to 
mark functions as exportable.

The type was called km_knp_option_set but the functions we called 
km_kbp_options_set_*

Export of action items still todo.

These will be needed by the state_to_json API call.