different fixes

Hello, @nitishsrivastava 

I created module for opencv using this library code: https://github.com/avdmitry/opencv_contrib/tree/deepmodels/modules/graphmodels
I don't know whether it will be useful for someone, but maybe opencv community will participate in this library development, at least I :)

In this PR I fixed some warnings, which I got and two issues:
1. I also got warnings for this: class which has virtual function usually also should have virtual destructor.
2. For operator new[] should be used operator delete[], otherwise there appear memory leaks.

Some other changes I work on (please let me know if you need them and I'll prepare PRs):
- technical thing: common practice - do not use "using namespace" in headers, because in this case the whole point of namespaces disappear. So I'll plan to remove such usings (in cc files "using" can be used)
- I added images processing using opencv (in current code there can be bugs, I still work on it) In this case we will not need dependences: jpeg, X11, CImg, tclap (I have removed them from opencv module already)
Also I found bug, probably in CImg library, currently it added blue line on images borders. Using opencv I fixed it.
- I think we can remove function: init_random_from_state from cudamat.cu, as looks like it will never be used.
- I think we also can remove src\sample.cc, as it is not really related to the library code.

And maybe sometime in the future I think will be useful to add to this library all functionality from your other library: deepnet.