Derive FileSystem::(Read/Write)Stream from std::(i/o)stream
fix warning in filecontainerzip.cpp
Split large macro definition for better debugging
Allow to "export" external canvas
Remove debug code
Fix bug with zip-container
Change extension of zip-container to "sfg"
Merge branch '0.64.1' into morevna

* 0.64.1: (23 commits)
  Fix Magick++ in OSX build
  Enable Magick++ module for Linux packages
  Make parameter list uses forbid animation icon instead of animate mod off icon
  Add forbid animation icon(used in paramerter panel)
  Use stroboscope and skeleton layer icons for layer tree
  Correct the canvas panel icon
  Add initial version of Stroboscope icon.
  Add skeleton layer icon.
  Update canvas panel and import image layer icons
  Cleanup by removing unused sif files according to the interpolation type icons update
  Delete unused sif interpolation type icon files
  Fine-tune interpolation type icons and using all icnos in one sif file concept to enable easy maintainance
  Cygwin build: Revert 3f05fb2b, because it's not really required
  Cygwin build: Fix environment switch procedure for pkg-config
  Cygwin build: Explicitly disable lzma in ImageMagick
  Cygwin build: Ensure we have cross-compile environment configured for imagemagick
  Bump ImageMagick version number
  Don't output MAGICKPP_LIBS variable at configure time, because it is optional dependency
  Fix #483 - Add support for Magick++ in Windows build
  MagickLib is deprecated. Replaced with MagickCore since ImageMagick 6.4.2.
  ...

Conflicts:
	synfig-core/configure.ac
Merge remote-tracking branch 'ivan/improve-zip-container' into morevna

* ivan/improve-zip-container:
  Change extension of zip-container to "sfg"
  Fix bug with zip-container
  Remove debug code
  Allow to "export" external canvas
  Split large macro definition for better debugging
  fix warning in filecontainerzip.cpp
  Derive FileSystem::(Read/Write)Stream from std::(i/o)stream

Conflicts:
	synfig-core/src/synfig/filecontainerzip.cpp