Add <Transform> support to <Connection> blocks in the skin.

Adds a general ValueTransformer class that does simple, invertible
transformations on numbers. We could re-use this in other places, e.g. MIDI
mappings to allow customizability to advanced users.
Merge branch 'master' into transform

Conflicts:
	src/skin/legacyskinparser.cpp
Change another occurrence of Analyser-> Analyzer, in Key detection preferences
Update translation templates. Found 1333 source text(s) (125 new and 1208 already existing). Kept 134 obsolete entries
Remove explicit g++ check since we aim to support clang (or whatever else is in the CC/CXX environment variable).
Delete unused code.
Remove SoundSourceProxy::ParseHeader in favor of the TrackInfoObject using the
SoundSourceProxy directly.
Update version and year in LICENSE.
Update copyright year automatically in OS X bundling.
Print some useful Qt debug information at boot-up.
Don't set the organization name since it results in incorrect (as we are using
it) QDesktopServices::DataPath results.

We don't use the app-store patch referred to in the comment anymore so this
should be fine.
Make bundle name (and binary name) upper-case on OS X.
Always build the codesign builder (otherwise we can get out-of-date signatures).
Fix default master output selection to use 2 channels.
Library scanner performance improvements.

For every directory, we were:
* Scanning the directory 3 times (once for hash, once for import, once for
  recursive descent).
* Continuously re-parsing the name-filters into regexps for every call to
  QDirIterator.

This change does one QDirIterator pass over the directory and uses a
pre-compiled QRegExp to check for compatible file names.

On a music collection of 18GB, 5000+ files and 1000+ folders, this produces a
20% speedup on first scan.
Improve language and logic.
On ARM, qreal is a float. Fix some cases where we pass a double* instead of qreal*.
Add arm64 and ppc64el to the machine whitelist.
Merge branch 'master' into transform

Conflicts:
	src/skin/legacyskinparser.cpp
	src/widget/controlwidgetconnection.cpp
	src/widget/controlwidgetconnection.h
Fix recent build copying on OS X.