added settings window
added identities list
Basic dialog with a few details, no signing yet
Key signing implemented
#31 Automatically fetch keys from keyserver
Merge pull request #42 from ag-mailcrypto/feature/auto-fetch-keys

#31 Automatically fetch keys from keyserver
refreshing keyring after signing one or more keys
Cleaned up settings screen
Merge pull request #43 from ag-mailcrypto/settings

Settings
Merge with master with some manual changes