Comment 4 for bug 896358

I think it's well to expand the techlevel rules.

there is the code example:
[Generals]
BuildupTime=.1
TechLevel5.BuildupTime=.5

[YuriCountry]
TechLevel2.VeteranUnits=LTNK

[NASAM]
Cost=1000
TechLevel6.Cost=1500
TechLevel3.Cost=2000

[105mm]
Damage=75
Burst=2
TechLevel8.Burst=1
TechLevel4.Damage=50

If the techlevel is higher than 3,4,6,8,the rules use its own
if the techlevel is 4,5,6,[NASAM]'s cost changed to 1500
And it's the same logic as unit/weapon/SW/aircraft/enginerules(such as oremine growthrate,orevaule,etc) TechLevel Rules and so on
Also the code Techlevelnumber.TechLevel is not allowed
This logic can used on artmd.ini