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
stat_accum_input: cleanup Flush() implementation

+ prepare code for setting custom namespaces
stat_accum_input: remove false timer messages

  When timer request with no timer values was processed Heka generated
false(?) timer messages as if timer 0 was sent. etsy/statsd seems to ignore
such requests.
stat_accum_input: fix timer calculation

+ added test to validate calculation results
stat_accum_input: use InputRunner.LogError instead of log.Println
added folderPerm to FileOutput plugin
Merge pull request #300 from mozilla-services/features/check_write_perms

fixes issue #232
Merge pull request #301 from pchojnacki/statsd_cleanup

stats_accum_input cleanup
Merge branch 'dev' into features/remove-stataccum-flushinterval

Conflicts:
	pipeline/stat_accum_input.go