Add basic pontoon bridge terrain type
Add construction for pontoon bridge

Numbers can be tweaked certainly.
Add tool_comp::by_charges to test whether tool requirements are for charges or for amount.

This only applies to tools, e.g. one welder (amount) vs. 100 charges of welder (100 batteries in the welder).

Components (items) always refer to an "amount", whether that amount is checked with has_amount or has_charges depends on the item being counted by charges or amount, not on the required number.
Therefor use std::abs for item_count::count (to handle negative values the same way as positives).
The actual required count (including batch factor) is calculated before decision of check of count_by_charges.
Fix welding rig requirements check:

forward the check to the item_comp and tool_comp classes, they know how to handle this.
Actual fix is to check for tools by count all the time (negative value as count).

Note: tool_comp::has calls inventory::has_tools
Note: item_comp::has calls inventory::has_charges or inventory::has_components
Fix quote

Whoops!
Loading items from old saves checks for items counted by charges that have no charges and repairs them.
Added shallow and deep version of pontoon bridge
Maybe add a separate pontoon_dp

Rather than forgetting to copy it and just changing it to pontoon_sh
Separate constructions for deep and shallow
Tweaked shallow recipe

1 drum, since they're a pain enough anyway.
Check vehicles, items and creatures when placing a tent.
Remove declaration of unimplemented function
Update terrain.json
Altered difficulty

Changed shallow pontoon bridge to 5
Update construction.json
Update construction.json
Update terrain.json
Merge branch 'bridge' of https://github.com/jokermatt999/Cataclysm-DDA into merge2
Merge branch 'fix-tent-placement' of https://github.com/BevapDin/Cataclysm-DDA into merge2
Merge branch 'fix-crafting-requirements' of https://github.com/BevapDin/Cataclysm-DDA into merge2