Long click on repo opens dialog

1) Navigate to repo owner's page
2) Remove repository from Recently Viewed

Also now refreshes repositories list when you return from
viewing a repo if the repo was added to the Recently Viewed list.
Previously, you had to manually refresh for the change to be seen.

Closes #348
Revert AvatarLoader whitespace changes
correct content description for avatar image
remove useless layout
imports optimize
extract string to resources
Extract duplicate code to single method.
Reduce scope of methods.

Closes #384
Change up navigation from RepositoryViewActivity
Navigate to the owner's page instead of the HomeActivity

Closes #316, closes #278
Improve Japanese translation

Closes #385
Remove duplication of methods in AvatarLoader, minor cleanup.
Make field immutable.
Convert private field to local variable.

Closes #386
no need for javadoc on private methods
caching avatars using urls, not userId

Closes #349
storing avatars in a separate folder for user

All avatars for a user are stored in a separate folder with the
user id as the name. All files in that folder are deleted before
writing a new one if the avatar doesn't already exist in that folder.
This should solve the problem with the old avatars when
avatar url is changed.
Remove unused parameters in CommitDiffListFragment

Remove unused parameter from private method,
reduce scope of local variables.
Closes #387
added a posibility to open commits compare screen for pull-requests. issues screen now has 'commits' button
commit icon near to 'commits' field
moved 'commits' label below the description