Parameter ordering of some field and group functions contradict API standards #406

I'd like to apologize in advance if this has been addressed already. I couldn't find mention of it in the issue tracker, so I thought I'd mention it.
The API parameter ordering guide outlined in secp256k1.h say that array lengths should always follow the argument whose length they refer to.

The following internal functions accept a length parameter before the object they refer to:

• secp256k1_fe_inv_all_var
• secp256k1_ge_set_all_gej_var
• secp256k1_ge_set_table_gej_var
• secp256k1_ge_globalz_set_table_gej

I know these aren't API functions so the standards may not apply here, but it may be worth reordering their parameters for consistency's sake.

Thanks for looking through this! Agreed, these functions should be consistent with the public ones (though in general, the public API guarantees do not apply to internal functions).

I've added a pull request (#407) to rearrange the parameter order for the above functions plus two extra.

(PR was merged)