Robot - Orient, Orientation, Specs & Gems added

- Added Orent, Orientation code to Robot and added test cases (Specs)
for verifying Oreint and Orientation.

- Added Gems required for Spec tests

- Updated README file with skeleton headings
Robot - left, right, specs added

- Added left, right methods to Robot class

- Added spec tests to robot_spec class which verify the left and right
methods added to Robot class.

- Updated README with left and right
Tabletop - Table, Specs added, README updated

- Added Table class having method to place Robot on Table when
co-ordinates are valid. Also a method to return the co-ordinates if the
Robot is placed.

- Added tabletop_spec having the tests to verify possible positive and
negative tests for each method added

- updated README file with PLACE
Rakefile Updated

- updated Rakefile to consider all spec files in specs folder
Robot Spec file updated for method name

- updated Method names to standard name to point to method name in
Robot class
Merge branch 'robot-specifications'