Changed function types related to SG days in date.c
Changed types in clif.c:
bool clif_setip -> map:ip_set, map: char_ip_set changed as well
bool clif_setbindip
bool clif_send
bool clif_spawn
void clif_homskillinfoblock
bool clif_sub_guild_invite
Note that return values of those types have changed, so if any modification uses their return values
it should be changed.

clif_disp_onlyself replaced as a macro
clif_viewequip_fail replaced as a macro
Merged clif_skillup and clif_guild_skillup as they were using the same packet
Added packet_len() values in clif_updatestatus