Renamed rc4 to arcfour.

Rev: lib/modules/Crypto/randomness.pmod:1.15
Rev: src/modules/_Crypto/StdCrypt.pike:1.5
Rev: src/modules/_Crypto/crypto.c:1.31
Rev: src/modules/_Crypto/crypto.h:1.4
Rev: src/modules/_Crypto/include/arcfour.h:1.4
Rev: src/modules/_Crypto/include/rc4.h:1.4(DEAD)
Rev: src/modules/_Crypto/lib/Makefile.in:1.21
Rev: src/modules/_Crypto/lib/arcfour.c:1.7
Rev: src/modules/_Crypto/lib/rc4.c:1.7(DEAD)
Rev: src/modules/_Crypto/testsuite.in:1.13