Prepend all macros with VV_ and make the C++ feature macros "positive".

Additionally add a macro to mark classes, class members or free functions as deprecated.
Move vvcompiler.h from private into the public directory
Use the macros defined in vvcompiler.h
Use size_t to store the size of the buffer
Make block size a parameter (prevent recompilation of vvrayrend.cu...)
Disable some more warnings when compiling with MSVC
Make hostXXX() const
Add override specifiers. Additionally make beginFrame/endFrame and resize only accessible by vvRenderer.
Add methods to download the color and depth buffers into a given buffer.
Add general methods to compress/decompress std::vector's. (Currently only compressing if Snappy is available.)
Add a vvMatrix constructor to construct a diagonal matrix
Add virvo::Image and virvo::IbrImage. The compression functionality of vvImage will be moved later into vvcompress.h/cpp
Delete unused header
Use the usual get and set methods
Add helper classes to simplify the use of the pthread API