Fix position of accel_init call (fixes multisystem test on GPUs)
Move accel_init out of system to run, before fft_init.
This is needed to make the GPU FFTs work - the accel part needs to be initialized before the FFT part. Moreover, accel is a global module and does not depend on system, so probably it's best to be initialized globally.
This also fixes the multisystem test on the GPU.
Fix position of accel_init (fixes multisystem test on GPUs).
- I have checked that my code follows the Octopus coding standards