Fix loading GCT into an anonymous module

[lgoettgens]

This seems to fix the issue experienced in oscar-system/Oscar.jl#5448 (comment).

I honestly don't really understand why it works like this, and if this is even a good idea to do. Maybe @benlorenz has some idea?

[lgoettgens]

Hmm, that was the reason we had all the relative module paths... Since the test setup needs it that way.... Then I have no immediate idea how to both satisfy the tests and the booktest setup...

[fingolfin]

We'll move away from evalfile, it was a bad idea in hindsight.

Will replace it with an eval/include based solution. All of course just a stopgap solution until #4 gets resolved

[benlorenz]

Something like this

function loadtab(path::String)
  mod = @eval module $(gensym()) end
  return Base.include(mod, path)
end

should probably work. evalfile will create the anonymous module below Main but this @eval should put it inside GenericCharacterTables, otherwise there is not really a way to reliably refer to GCT.

Edit: While testing this I noticed that the same file gets loaded again and again if I re-run the generic_character_table command.

[SoongNoonien]

Replaced by #309.