Merge branch 'erp5-component' into erp5
slapos stack: Add new explicit dependencies of slapos.core.
Add missing copyright & license header.
Raise UserError instead of Exception.

Buildout output is less scary this way.
Add missing copyright & license header.
Raise UserError instead of Exception.

Buildout output is less scary this way.
version up : libpng 1.6.2 and specify so version.
version up : FreeType 2.5.0.1.
version up : poppler 0.22.5.
version up : webp 0.3.0 and specify so version.
Merge branch 'master' into erp5-component
Merge branch 'erp5' into erp5-component