Make Shift+<Hotkey> queue five units/buildings. Fixes #5544.
Cache tileset lookup in map so GetTerrainIndex and GetTerrainInfo need not repeat it every time.

The lookup accounts for ~50-60% of the time spent in GetTerrainIndex and GetTerrainInfo, and these methods themselves can account for up to 1.3% of total CPU used so this is a small but measurable win.
Fix fallout from tech-capture changes
Merge pull request #5763 from obrakmann/build-shift+keypress

Make Shift+<Hotkey> queue five units/buildings. Fixes #5544.
Merge pull request #5762 from obrakmann/fix-tech-capture-fallout

Fix fallout from tech-capture changes
Merge pull request #5751 from RoosterDragon/map-cache-tileset

Cache tileset lookup in Map