added a check to make sure we can actually write to the dashboard
output files
fixed typo in configuration docs for dashboard output
added a write test to make sure the top level whisper directory is
writeable on plugin Init
added a check to create the basepath and check the write permission in the basepath for FileOutput
move checkWritePermission to the main output.go file
resolves issue #232

The FileOutput plugin will now create the parent directory if it doesn't exist and check that we have write permissions on the parent directory.
Dashboard plugin will also check for write permissions and cause the system to abort on failure.
Merge branch 'dev' into features/check_write_perms

Conflicts:
	pipeline/outputs.go
	pipeline/whisper.go
added folderPerm to FileOutput plugin
Merge pull request #300 from mozilla-services/features/check_write_perms

fixes issue #232