Create polls (#1452)

* add AddPollDialog

* add support for pleroma poll options

* add PollPreviewView

* add Poll support to drafts

* add license header, cleanup

* rename drawable files to correct size

* fix tests

* fix bug with Poll having wrong duration after delete&redraft

* add input validation

* grey out poll button when its disabled

* code cleanup & small improvements

app/src/test/java/com/keylesspalace/tusky/ComposeActivityTest.kt

@@ -28,7 +28,6 @@ import com.keylesspalace.tusky.entity.Instance
 import com.keylesspalace.tusky.network.MastodonApi
 import com.keylesspalace.tusky.util.ThemeUtils
 import okhttp3.Request
-import okhttp3.ResponseBody
 import org.junit.Assert
 import org.junit.Assert.*
 import org.junit.Before
@@ -258,6 +257,7 @@ class ComposeActivityTest {
                         emptyList()
                 ),
                 maximumTootCharacters,
+                null,
                 null
         )
     }