add troubleshoot hint for case when change-list is empty
do Git operations against Gerrit remote

- it just used to take the "first" remote before which was not always the Gerrit one

Resolves #14
bump version to v0.5.0
show review notifications for all changes

- instead only of changes from currently open projects
- fix warn notifications that no Git repositories are available because of loading order (review notification gets loaded early in startup project loading process))
minor cleanups
add support for anonymous users

- if no username / password is entered, requests are done without user information
- allows at least read-only operations with Google Gerrit instances

Related to #44
set connection timeout to 30s

- since we do HTTP operations asynchronously now, it may be higher
port from commons-httpclient v3 to apache.httpcomponents v4

- fixes at least some ssl issues (certificates with broken chain)

Resolves #26
Related to #43
simplify ssl support after porting to apache.httpcomponents v4

- requests can be reused after resetting
fix prompt for untrusted ssl certificates

- wrong (old) host got prompted in settings instead of the newly entered one
update testng to v6.8.7
update testng to v6.8.7

- update .iml file
use IntelliJ action infrastructure more consistently

- allows user configuration (e.g. keyboard shortcut)
add plugin version to HTTP user agent
show star icon for starred changes in list

Related to #30
add support for PUT HTTP operations
add action to change starred status of a change

- supported with Gerrit >= 2.8

Resolves #30
add support for file comments on both sides (parent and revision)
set file review status to reviewed when opening files in diff viewer

- review status is not visible in plugin yet (only web ui)
- review status cannot be changed in plugin yet

Related to #20
add note to error message that start feature is only supported in Gerrit >= 2.8