- My usual test environment has umask set to 022, but on one dev
   box it is 002, leading to test failures (which show the test
   was bad, not that the umask-setting code is bad)

 - not really sure why I went for the Qt 5.10 STL-style iterators

FIXES #1236

[unpackfs] Enable to use "/" as a source

add esperanto branding translations, fix mis-configured ones

 - Use any object method to connect() to

 - sometimes a slot is easier than a lambda. Introduce
   a macro CALAMARES_RETRANSLATE_SLOT that calls a given
   slot in an object on language change.
 - extend the retranslator with support for calling slots:
   - use Qt's signal/slot mechanism alongside the private
     list of functions to call
   - provide convenience for obtaining the retranslator of
     an object.

 - This helps give meaningful names to code chunks
 - Gives clang-format something to work with
 - Reduces indentation depth

I think this is a bit of a code-style opinion issue: big complicated
lambdas doing UI things just don't seem like a good idea.

 - the RETRANSLATE macro is a real challenge for astyle and clang-format

eliminate magic number in src/modules/welcome/WelcomePage.cpp

cross-reference/clarify geoip documentation

update doc comment in src/modules/initcpio/initcpio.conf

fix typo in comment src/libcalamaresui/ViewManager.cpp

FIXES #1213

Better slideshow loading, both V1 and V2. Keyboard shortcuts only while
the slideshow is visible.

 - since we also need to *disable* the shortcuts, and should tell a
   V1 slideshow that it no longer is running,
 - use existing function to set the property to true / false depending.
 - instead of changeState( true ) or changeStage( false ), use
   meaningful enum names so that the code at the call site
   becomes readable; make the boolean part internal to the
   state-changing method.

 - when the QML is activated, if the slideshow has this property,
   set it to true. This enables the keyboard shortcuts.

 - one function for activation, since we activate from different
   places and each loader-API may need multiple steps for activation.

 - with V2 loading, the key shortcuts should be enabled when the
   slideshow itself is activated, not when it is loaded.