add failing test when explicitly set layout to false in _data.json

When explicitly set layout to false in _data.json and put a file
in the outside directory with the same name as the directory name
and a template extension, that file will be used as layout. In the
test case, the file is false.jade outside the false/ directory.

This is because false is not explicitly checked in the layout
lookup, and is treated as empty string.
explicitly catch layout set to false case, and set layout to null
adds .travis.yml file
cleaned up whitespace in yml file
now have a valid travis file
adding node v0.8 to CI list
Change mocha for Windows
Merge pull request #15 from kennethormandy/patch-1

fixes windows testing script
Merge pull request #13 from echaozh/fix-layout-set-to-false

Fix layout rendering issue when layout is explicitly set to false
version bump v0.5.4
bumps jade to 0.35.0
fixes jade test error
updates jade fixture to force error
bumps marked to v0.2.9
bumps less to 1.4.2
bumps stylus to 0.38.0
resolves missing line number in jade errors
fixes line number ref for windows
fixes paths in layout test. for windows.
splits urls with slash instead of path.sep