Fix console-input in SDL1.2 for lots of unmapped keys

A lot of keys (especially keys not available on US keyboards) just weren't
supported for console input with SDL1.2 (SDL2 uses a different mechanism for
that).

This is fixed now by reordering a few lines in sdl_events.cpp

Please note that still only ASCII characters are supported and those keys
still can not be used in bindings - only for text input!

Fixes https://github.com/RobertBeckebans/RBDOOM-3-BFG/issues/34

__This needs testing before it can be merged!__