Release 1.2.0 - 20.04.2020

NEW FEATURES
- Calibration: added new camera calibration module, with better UI and
  support for stereo calibration.
- Cameras: originDescription in data streams now more concise and unique.
- eDVS: added 'cameraID' configuration attribute to specify a custom serial
  number, to allow the user to disambiguate multiple cameras.
- MacOS X: set default CMake destination to /usr/local on Apple systems.
- File/Netork Output: implement 'timeout' parameter to stop recording after
  a certain time has passed (issue #292).
- Core: added support for Google Perftool's head and CPU profilers.
  Please see the relevant NOTE in README.md.
- Services: added OpenRC init script, improved systemd install script, used
  more standard paths for systemd init script, added sysusers support.
- Ubuntu: support for release 20.04 LTS 'Focal Fossa'.
- dv-runtime CLI: -a 0/1 and -b 0/1 command-line options to dv-runtime are
  now only valid for that particular dv-runtime invocation and are not saved
  as part of the permanent XML configuration, nor do they modify it (issue #240).
- ConfigServer: various improvements, all GET* requests now return the full
  attribute information, type specification is not needed anymore.
- dv-control: new get_type command, type specification not needed anymore.
- SDK API Portable IO: added C++ variants of portable IO functions.

BUG FIXES
- MacOS X: fix duplicate-symbol linker error with Apple Clang compiler and
  TLS __getDefaultConfig() function variable when including <dv-sdk/module.hpp>
  into multiple compilation units within the same module.
- File Input: fix reset of 'seekEnd' configuration attribute if manually removed.
- SDK API Types: add missing const to TimeElementExtractor argument.
- SDK API portable_get_user_home_directory(): correctly handle getenv() and
  getpwuid_r() failures.
- Config / Log: write temporary configuration and log files to global temporary
  directory to avoid permission issues, original system directories might not
  allow writing to dv-runtime user.
- ConfigTree: ensure attribute updaters are removed when their corresponding
  attributes or nodes are, to avoid dangling references (issue #212).
- Modules / Log: per-module log-level now only applies to messages originating
  from user functions within a module, all other messages use the system
  log-level (issues #226 and #246).