Remove: [Script] CONFIG_RANDOM from AddSetting flags (#11942)

It had a very weird interaction, and was only ever used by a single
AI.

Codechange: Make SpriteType, CargoSortType, SourceType and ScriptType enum classes. (#10663)

This avoids a (soft) namespace conflict between the four ST_* enums.

Change: replace per-AI "start_date" with a global "competitors_interval" (#10653)

The per-AI "start_date" is a lot of custom code, and was rarely
used in the way it was meant.

While at it, also ported this part over to the new timer system.

Change: rebrand 1.12.0 to 12.0

One question that keeps popping up: "when do we release 2.0?".
NewGRF will force that at least 1.16 will be 2.0, but to not wait
for this, let's drop the "1." and be for ever done with that
conversation.

We are following in the footstep of giants here.

(svn r17214) -Add [NoAI]: GetAPIVersion() as optional function in info.nut. Return "0.7" to get an api compatible (as much as possible) with the 0.7 api or "0.8" to get the latest api.
-Change [NoAI]: move all deprecated functions to a separate squirrel script that is only loaded if an AI requests an old API version.

(svn r15095) -Add [NoAI]: allow AI Libraries to be in .tar files (subdir required, as with AIs
-Add [NoAI]: allow multiple versions of the same AI co-exist
-Change [NoAI]: updated the whole method of AI (Library) finding and loading; it is now much more clear and transparent
-Change [NoAI]: the name of the AI is now the name used by CreateInstance()
-Change [NoAI]: make the AI finder a bit more clever, mostly related to version finding

(svn r15063) -Fix [NoAI]: starting companies now listen correctly to 'start_date' set to the AI slot (Yexo)
-Add [NoAI]: add a 'deviation' value for all settings, giving a slight deviation of the value of a setting (Yexo)

(svn r15045) -Add [NoAI API CHANGE]: in info.nut you can now have (optional) a CanLoadFromVersion(version), which should return true/false, to indicate if you can load a savegame made with your AI of version 'version'
-Add [NoAI API CHANGE]: in main.nut the Load() function now should be Load(version, data), where 'version' is the version of your AI which made the savegame
-Codechange [NoAI]: various of function renames to make things more sane
-Add [NoAI]: push the 'version' of the AI through various of layers
-Codechange [NoAI]: various of code cleanups
-Add [NoAI]: store the version of the AI in the savegame too

(svn r15027) -Merge: tomatos and bananas left to be, here is NoAI for all to see.
NoAI is an API (a framework) to build your own AIs in. See:
http://wiki.openttd.org/wiki/index.php/AI:Main_Page
With many thanks to:
- glx and Rubidium for their syncing, feedback and hard work
- Yexo for his feedback, patches, and AIs which tested the system very deep
- Morloth for his feedback and patches
- TJIP for hosting a challenge which kept NoAI on track
- All AI authors for testing our AI API, and all other people who helped in one way or another
-Remove: all old AIs and their cheats/hacks