nnForge v1.1.6

I implemented a number of quite useful features in nnForge recently:

• Stochastic Gradien Descent training method is added
• Resume training fuctionality added
• Duplicating output to log file
• Logging current settings at the toolset initialization
• rgb_to_yuv_convert_layer_tester added in CPU backend
• Readers are redesign to allow variable data readers
• classifier_result is extended to top-N
• Added possibility yo split single reader into multiple epochs
• Multiple fixes