Update script_commands.txt

Added documentation for switch statement.
Minor fix on BG script.

Based on this report.
http://rathena.org/board/tracker/issue-8813-minor-warning-on-battleground-script/
Merge pull request #60 from sandbox-ra/patch-6

Added 'switch' statement documentation to script_commands.txt.
Merge pull request #63 from sandbox-ra/patch-7

Minor fix on BG script. (bugreport:8813)
http://rathena.org/board/tracker/issue-8813-minor-warning-on-battleground-script/
Fixed some equip location itemscripts. (bugreport:8821)
http://rathena.org/board/tracker/issue-8821-general-daehyon-card/

Added official names as comments in many newer scripts.

Signed-off-by: Euphy <euphy.raliel@rathena.org>
Added the remaining part to the official expiration timer. (Hercules 7120b55)
Minor fix on siege set combo.

Based on..
http://rathena.org/board/tracker/issue-8825-siege-suit-set-bonus/
Merge pull request #64 from sandbox-ra/patch-8

Minor fix on siege set combo. (bugreport:8825)
http://rathena.org/board/tracker/issue-8825-siege-suit-set-bonus/
Merge branch 'rathena/master'