finalized helper tests. additional tweaks to Plan tests

Updated projects_helper by renaming 'project_list_column_body' to 'plan_list_column_body'. updated references to that code block. moved hard-coded 'Unknown' to locale files. Added tests for projects_helper

finished application_helper tests

added initial application_helper tests

added simplecov gem for testing to provide us with a test coverage report. Added a test for application_helper.rb. Removed tab characters from application_helper.rb and added some lines to help with readability