Forgot to save gamma correction

Signed-off-by: Mattias Andrée <maandree@operamail.com>
Do not run malloc all the time on windows version either

Signed-off-by: Mattias Andrée <maandree@operamail.com>
store gamma correction in state for gamma-w32gdi

Signed-off-by: Mattias Andrée <maandree@operamail.com>
gamma-dummy should not fail if gamma is set, also add #include to gamma-w32gdi that i missed

Signed-off-by: Mattias Andrée <maandree@operamail.com>