TweetListEntry: Remove the inline reply revealer

It was kinda weird to have 2 completely different ways to reply to a
tweet. Also, the inline reply really tried to be too much UI in too less
space -- didn't display how many characters are left, didn't preview the
inline media, etc. -- so just remove it and show the usual
ComposeTweetWindow which just directly grabs the keyboard focus so no
need to switch to the mouse.
Also makes instantiating a TweetListEntry faster.
TweetUtils: Minor style correction
Merge branch 'master' of https://github.com/baedert/corebird

Conflicts:
	ui/tweet-list-entry.ui
Partly move to using GActions

... and in the same step, make key accelerators at least partly
configurable.
TweetListEntry: Show the reply_button again

It mysteriously disappeared in 6605bc7cc3cb83390c6bc073db358fa01c0ba447
Move Alt+Num Shortcuts to GAction, too
MainWindow: move more stuff into the ui file
MainWindow: Remove the WarningService

It didn't do anything and I have other plans for its functionality.
Merge branch 'master' of https://github.com/baedert/corebird
tweet-list-entry: Give the rt_label some margin_top
tweet-list-entry: Add tooltips to the inline buttons

See issue #81
UI: Add tooltip texts to the various sidebar buttons

and make their labels translatable.
Merge branch 'master' of https://github.com/baedert/corebird
TweetListEntry: Remove the rt_label if the tweet is no rt
TweetListEntry: Slight refacroting
TweetListEntry: Remove the delete menu item if it's not suitable
TweetListEntry: Make the time delta just text

we will introduce the link in the tweet details.
TweetListEntry: Move the hover buttons to the right

So they just consistently keep their position no matter what. Will also
simplify pretty much everything.
UserStream: Also print the acccount name on heartbeat
TweetListEntry: Correctly set the hover_box's margin_right