1. Move all files in kernels to ops
2. unify the op_def_registry and op_registry.
3. Support op clip: do not link the ops' code when the op is not registered.

* fixing library path in host benchmark

* applying reviewer's comment - ensuring proper line length

1. Quantize weights
2. Add quantize-dequantze nodes

Some devices generate `adb devices` message with `-` which
is ignored by current tools. This patch enables them.

Fix cast from bool

See merge request !619

Revise memory allocation logic to make non-float output possible