updated to vuforia-sdk-ios-2-8-7

replaced includes and the lib file.
updated to vuforia-sdk-ios-2-8-7

No features added just support for the latest SDK.
updated licenses for 2-8-7
implementation for extended tracking

startExtendedTracking()
stopExtendedTracking()
support to load multiple target definition files at runtime

This update allows to add additional target definitions at runtime. The
limit for the summ of all targets within all loaded files is 100.

In the exampleET only the chip target is active. Once double tapped on
the screen an additional target file is loaded and the other two
targets become functional.
internal tests
Merge pull request #9 from vheun/master

updated to vuforia-sdk-ios-2-8-7