This empty line is required as delimiter between third-party headers and robomongo headers.

This is described here:
http://www.mongodb.org/about/contributors/kernel-code-style/#includes

Google C++ Style Guide also follow this convention:
http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml?showone=Names_and_Order_of_Includes#Names_and_Order_of_Includes