Make matrixBandPart work with other integer types than INT64

[carlo-veezoo]

I would expect the following code to work:

import org.platanios.tensorflow.api._

object MatrixBandPart {
  def main(args: Array[String]): Unit = {
    tf.matrixBandPart(Seq(Seq(0)), 0, 0)
  }
}

However it does not, because matrixBandPart expects INT64 arguments. The changes make this work, and introduces checks to not cast e.g. float.

[eaplatanios]

Good catch! :)

[eaplatanios]

@csaladin94 FYI if you want to show up as a contributor and make sure your commits are linked to your account, you should associate carlo@veezoo.com with your GitHub account. :)

[carlo-veezoo]

@eaplatanios Thanks for the information, I just did that!