Added element wise floor functionality

Element wise Ceil and Floor both work now.

Rectified some mistakes in the code.

Reworked floor and ceil.

Removed casting from floor and ceil mappers.

floor and ceil work properly for all but complex

floor and ceil working well.

removed c++ code

optimized
Merged new changes from parent branch
weird rspec error
added ruby object
removed newline
Merge branch 'master' of https://github.com/SciRuby/nmatrix
Fixed bug with ruby object typecasting. Floor and ceil work great now.
Rectified some errors in conversion to ruby object.
Exception handling added.
Amended Travis CI build error.
Typecasting fix
Merge branch 'master' of https://github.com/SciRuby/nmatrix