Fixed CleanPollution and CleanFallout activities to respect extra removal
requirements.

See bug #22312


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@25580 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Initialize tech_bulb_sum before starting to add cost components to it
in tech_upkeep_calc().

See bug #22321


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@25581 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Adjusted working of alien ruleset Thick Mountains
- Road building time reduced to 12 movement points
- They cannot be mined before Burrowing is known
- Mining time reduced to 17 movement points

See patch #4941


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@25582 a0f10bec-cc02-0410-94fc-a9cfff90b4cd