Log Message:
Update mikutter to 3.4.0.

Upstream changes (from 3.3.x, which include changes during alpha releases):

* library
 * Pluggaloid 1.1
* "open tweet" function
* profile
 * brush up UI
* a bunch of settings for reply tweet view
* a bunch of settings for quoted retweet view
* fix issue that clicking video links just showed thumbnail image
* drop Ruby 2.0 support and requires 2.1 or later
* Cairo::SubPartsMessageBase
 * "tweet in tweet view" function used for reply and quoted tweets,
   which can be used third party plugins
* graph of plugin dependency now can be used by mikutter sources
* plugin dependency now can be put into dot file