fix file comments on windows

- windows uses backslashes, but Gerrit always requires forward slashes
- thanks to yurks for testing this change

Resolves #93
fixes for anonymous access

- do not try to load draft comments
- do not try to set file review status
register shortcut 'C' in editor content only

- fix using character 'c' in editor search

Resolves #103
update changelog

- bump version to 0.9.1-SNAPSHOT
fix error handling for update notifications

- use GerritUtil which properly handles errors (e.g. authentication errors)
disable action for anonymous which require authentication
bump version to v0.9.1