* Refactored DisposableObject

* Added different build directory for TensorflowNET.Examples.GPU

* _FetchHandler: Switched to NPTypeCode

* gfile.cs, Walk(...): Handle case when directory top doesn't exist.

* Tensor.Creation: Perf-opted when creating tensor from NDArray of string

* Graph.cs: refactor and added docs

* Tensor.Creation.cs: perf-ops

* Tensor.Explicit.cs: perf-ops

* Copied globals.regen from NumSharp

- Added supported_numericals_TF_DataType

* Tensor perf-ops and cleanup, Revamped dtypes.cs, some renames.

- Cleanup and docs to all Tensor.cs files
- Changed all uses of System.Convert to NumSharp.Utilities.Converts
- Added all missing types in dtypes.cs
- Renamed tensor.Data<T> to tensor.ToArray<T>, added obsolete message
- Renamed tensor.Data() to tensor.BufferToArray(), added obsolete message
- Made GraphKeys to use const string instead allocating strings at every use of GraphKeys.

* Tensor: Added guards for explicit casts.

* Tensor: Added explicit cast to string

* Tensor.ToArray<T>(): Added support for cases when tensor is scalar.

* Tensor.BufferToArray(): Fixed to use long instead of int.

* TensorShape: Revamped and documented.

* BaseSession: Added Session.run(ITensorOrOperation fetche, params FeedItem[] feed_dict)

* Tensor: renamed _dtype to _override_dtype

- Fixed all locations _dtype is used incorrectly.

* Fixed unit tests

* Tensor.Operations: Reverted commit

* DisposableObject: sorted internal_dispose to properly handle Dispose() calls

* Tensor.DisposeUnmanagedResources: Nullify _handle after delete.

* TensorShape.this[...]: fixed guard check.

* DisposableObject #362

Relative unit test in `OperationTest`.

Relative unit test in `OperationTest`.

Relative unit test in `OperationTest`.

Relative unit test in `OperationTest`.

Relative unit test in `OperationTest`.

Relative unit test in `OperationTest`.

* Add missing `operator >=`s

Also unit testing the new operators.

* Add missing `operator <=`s

Also unit testing all the operator cases.

* Add missing `operator >=`s

Also unit testing the new operators.

* Add missing `operator <=`s

Also unit testing all the operator cases.

* Add missing `operator >`s

Also unit testing all the operator cases.

* Add missing `operator <`s

Also unit testing the new operators.

Also unit testing the new operators.

* adding unit tests

* ignoring failing tests

* removing ignore from unit tests

Unit testing the operation too.

Exposing also the `IsFinite` one.
Unit testing both operations.

- Concat
- LGamma
- Tanh
- Slice

* removing unused namespaces

* implementing Tensor to scalar and scalar to tensor conversions

Unit testing the gradient too.

Also unit testing all the operator cases.

Also unit testing all the operator cases.

Change nest.flatten to generic.