- gcm128.c: support for Intel PCLMULQDQ, readability improvements;
- asm/ghash-x86.pl: splitted vanilla, MMX, PCLMULQDQ subroutines;
- asm/ghash-x86_64.pl: add PCLMULQDQ implementations.

- introduce common modes_lcl.h;
- ctr128.c: implement additional CRYPTO_ctr128_encrypt_ctr32 interface;
- gcm128.c: add omitted ARM initialization, remove ctx.ctr;

ghash-x86*.pl: fix performance numbers for Core2, as it turned out
previous ones were "tainted" by variable clock frequency.

change.

subject to change...