kijiproject.github.com: KijiExpress tutorial.  Update language page.

Fix minor issues in example script (previous script would not run).

Make uses of "variable" versus `variable` consistent.

Add an extra "project" call to example (to remove extra fields).
commit: https://github.com/kijiproject/kijiproject.github.com/commit/55c2fb3276d86de17af4feb57ac0734438d4d8dd