2.34.0 feature release

Deprecation notices:
* --package egentoo is no longer supported.
  See "New .gpkg.tar package format for Gentoo" for information about the supported --package gentoo option.
* --package gentoo + --compression auto can no longer be used together.
  The new default for --package gentoo is --compression none.
* The legacy dependency system relying on PKG_xxx_DEPS variables can now only be used to set dependencies on sibling packages.
  The following dependencies variables should be used instead of PKG_xxx_DEPS:
  - PKG_xxx_DEPENDENCIES_LIBRARIES, to list native libraries (./play.it ≥ 2.18)
  - PKG_xxx_DEPENDENCIES_MONO_LIBRARIES, to list Mono libraries (./play.it ≥ 2.21)
  - PKG_xxx_DEPENDENCIES_GSTREAMER_PLUGINS, to list GStreamer decoders (./play.it ≥ 2.23)
  - PKG_xxx_DEPENDENCIES_COMMANDS, to list commands (./play.it ≥ 2.25)
  - PKG_xxx_DEPENDENCIES_SIBLINGS, to list sibling packages (./play.it ≥ 2.30)
* Support for legacy APP_REGEDIT variable is dropped.
  WINE_REGISTRY_INIT, introduced with ./play.it 2.33, should be used instead.

New .gpkg.tar package format for Gentoo:
* Generation of packages using ebuild is replaced with .gpkg.tar packages,
  relying only on coreutils, tar and compressors.
* Packages for Gentoo can now be generated from systems not providing ebuild.

Improved support for Web games:
* Web games are no longer run using the shipped Google Chrome build,
  but with a local Web server (using the server built into Python)
  and Firefox to provide the graphical interface.

Improved support for Unreal Engine 3 games:
* Inputs related problems are avoided:
  - ignored keyboard inputs
  - broken mouse camera control

Improved support for GameMaker games:
* A crash on Mesa is avoided.
* Broken support for non-US locales is worked around.
* The following variables can be omitted:
  - APPLICATIONS_LIST
  - APP_xxx_EXE
  - APP_xxx_ICON
  - CONTENT_GAME_BIN_FILES
  - CONTENT_GAME_DATA_FILES
  - PACKAGES_LIST
  - PKG_BIN_DEPENDENCIES_SIBLINGS
  - PKG_BIN_DEPENDENCIES_LIBRARIES
  - PKG_DATA_ID
  - PKG_DATA_DESCRIPTION

Archives with multiple valid MD5 hashes:
* ARCHIVE_xxx_MD5 is expanded to support multiple values.
  Multiple valid values should be separated by line breaks, empty lines are ignored.
  Here is an example usage:
  ARCHIVE_BASE_2_NAME='setup_jazz_jackrabbit_2_1.24hf_(16886).exe'
  ARCHIVE_BASE_2_MD5='
  25a730c0813eb006555e6bbaf9613487
  45be80bad040ea821bc6096abe6f3196
  48a48258ed60b24068cbbb2f110b049b'

Improvements to menu entries for desktop environments:
* Support is added for SVG icons.
* The value set through APP_xxx_CAT is checked against a set list of valid values,
  and a warning is triggered if an unknown value has been set.

Improvements to WINE registry support:
* WINE_REGISTRY_INIT now has support for contextual values (package-specific or archive-specific).
* Only the key name is used when generating a regedit dump. This should avoid problems with dump paths going over the length limit for regedit.
  Old dumps are not automatically migrated to the new path. This can be done manually by running the following commands:
  DUMPS_PATH=~/.local/share/games/${game_name}/wine/regedit/
  find $DUMPS_PATH -name \*.reg -exec mv --target-directory=$DUMPS_PATH {} +
  find $DUMPS_PATH -type d -empty -delete

Rework of package dependencies listing:
* This update reduces the difference between distinct dependencies listing systems
  (commands, GStreamer decoders, Mono libraries, native libraries, sibling packages)
  as well as between distinct target package formats (Arch Linux, Debian, Gentoo).