Bugfix: don't focus unmapped container on manage

A window may become unmapped on manage when an assignment command unmaps
the window, such as moving it to the scratchpad or killing it.

This can cause i3 focus to be an unmapped window and different than X
focus which can lead to complications

fixes #1283
Merge branch 'fix-focus-unmapped'
add log messages for the detected DPI

Currently, the DPI is only logged when pango fonts are used, which is
often not the case when people report problems with the DPI detection.
Merge branch 'log-dpi'
Bugfix: interpret commandline parameters as utf-8

fixes #1293
Merge branch 'fix-i3-save-tree-unicode-args'
Bugfix: create the directory for storing the restart state (Thanks hjem)

fixes #1303
Merge branch 'fix-restart'