Committing the code of 1.4

Additions:
- Added delays
- Added dates
- Added local variables ({*local variable}) which are local to the (Bukkit) event
- Added expression 'difference of/between <object> and <object>'
- Added expression 'facing of <entity>' and 'horizontal facing of <entity>' which gets the closest cartesian axis in which an entity is looking
- Added expression 'IP of <player>'
- Added expression 'random integer between <number> and <number>'
- Added expression 'actual targeted block of <player>'
- Added expression 'type of <item/entity>' to get the type of an item (i.e. id and data without amount, enchantments, etc.) or the type of an entity (e.g. player or wolf)
- Added effect 'ban' which can ban players by name or IP
- Added effect 'ignite <entity>' to set entities on fire and an effect 'extinguish' if you don't want them to burn anymore
- Added effect 'strike lightning at <location>' to strike lightning at a specific location
- Added effect 'shoot <projectile> from <entity>' to shoot projectiles (or other entities =P) from some entity
- Added effect 'toggle' to toggle a block's state
- Added condition '<player/IP> is banned'
- Added condition '<entity> is in <world>'
- Added condition '<entity/item> is of type <type>'
- Added condition '<player> is online/offline'
- Added condition '<player> has played [on this server] before'

Improvements:
- Blocks are now placed smartly
- Added version number to variables.csv for automatic conversions
- Automatic detection of possible variable name conflicts
- Changed the way variables are deleted
- Skript now tries to create a backup of variables.csv if it can't read from it
- Improved performace of getting class infos which is used very often
- Script are now loaded from subfolders of the scripts folder as well
- A warning is printed if no scripts were found
- Added information on how long it took to load all scripts on server start
- Changed the expression 'event-<type>' (e.g. (event-player) to hopefully work better
- Improved property expressions (expressions like '<property> of <object>', e.g. 'world of player')
- The '(de)op' effect can now also (de)op players who are not online
- The 'poison <entity> for <timespan>' effect now prolongs an existing poison effect instead of overriding it
- A warning is printed if an empty configuration section is detected
- The 'chance of <number>%' condition now properly accepts expressions as chances
- Some other improvements which I don't remember

Fixes:
- Fixed variables (again)
- Skript should now be compatible with Tekkit and other Bukkit implementations
- Fixed not being able to execute custom commands with the command effect
- Fixed the expressions 'block' and 'entity/player/etc.' not printing an error if there's no block/entity/etc. in the event
- Fixed not being able to get a sign's text in a sign change event
- Fixed the pressure plate event throwing an error when used
- Fixed the effect 'exit/stop 1 section' not printing an error if there's no section to exit from
- Fixed the 'teleport' effect throwing an error if using it in a player respawn event
- Fixed the indentation error message
- Fixed the 'is raining/sunny/thundering in <world>' condition from misbehaving in weather change events
- Some other fixes which I don't remember

Known issues:
- 'players' is the same as 'player' even though it should be the same as 'all players'