added method to get table headers to uiadll
Table#headers
can get values from a table in uiadll
added method to clean up string arrays returned from uiadll
UiaDll#strings_from -> class method
favor rspec let in table spec
Table#values
Table_GetValues includes ListItem controls as well in uiadll
refactored Table#strings to use new uiadll string methods
DRY up some string copying
remove #headers and #values from the Table api
remove unused Functions#retrieve_table_strings_for_row for win32 and msuia
remove unused Window#oleacc_module_handle for msuia
Merge branch 'Table#strings' of git://github.com/leviwilson/RAutomation into leviwilson-Table#strings

Conflicts:
	ext/UiaDll/Release/UiaDll.dll
Merge branch 'msuia-oleacc-removal' of git://github.com/leviwilson/RAutomation into leviwilson-msuia-oleacc-removal
Speed up building external dependencies by not even invoking msbuild when it is not needed by using Rake file tasks.