The parameterless Platform::Context::Context() constructor and
Platform::Context::tryCreate() function are deprecated in favor
functions that take argc/argv pair. The Context class now accepts
arguments starting with --magnum-* prefix. Currently there are none
except for the implicit --magnum-help, but that will change with the
following commits.
In some cases the GL context creation might success without error, but
the created version is one that we don't want (e.g. software GDI
rasterizer on Windows). Previously the Context class constructor just
exited the application and it was impossible to react on that from the
application side (for example reducing some context feature
requirements).
Now there is Platform::Context::tryCreate(), which returns either
created instance or `nullptr` if the instance creation failed with some
error. That is now used in all Platform::*Application implementations.
It returns CGL version and not the GL one, obviously. The original check
was suspiciously broken so I "fixed" it in
d54be041c4 and rendered this class
practically unusable. Sorry.