detector/descriptor.

There's no need, since configure_file writes its output using native
line endings, anyway.

VideoWriter memory leak solved.

Android 4.3 support added;
ANY camera index support fixed;
applyProperties now uses camera->reconnect() instead close/connect for Android 4.x.

Also, added the missing include guard to perf_precomp.hpp.
This should fix the build.

Looks like we don't actually use them; when creating precompiled headers
with Visual C++, a dummy .cpp is created at build time.