Set up smashable paved bridges

These are for use in world gen, although the code isn't there yet. Some adjusting on the bashing numbers may be needed, as this is an entire tile of bridge being bashed down.
Update terrain.json

Fix json errors
add wrenchable flag to small storage battery.
Wrenchable means can be added and removed by a wrench
Added processing of wrenchable flag. There appears to be a vanilla bug
where a jumper cable and a wheel installed on the same part causes the
wheel to be removeable without proper equipment. Affects wrenchable type
too.
Fixes vehicle remove checking if part is a wheel or a cable, or anything
else that doesn't need the standard suite of tools
added comments, removed redundant variable
Separates out core checking of valid part select from do_install
fixed drive system conflicts
refactor
Can now add and remove items with WRENCHABLE flag, if have a wrench.
Modified install process so that a list of possible items to install is
displayed, even if you have no tools. It still lists when a tool is
missing,so that should be fine
Corrected install message for wrenchable items, to only require a wrench
as a tool
Fixed ui relating to install of wrenchable parts
Fixed plural message for parts remove
Fixed message for is_loose remove
Renamed wrenchable to tool_wrench, add tool_none for hand removal.
added flags to all batteries
fixed mechanics skill check
removed some redundant code
fixes unremovable regular parts
fixes wheel removal without jack
made UNMOUNT_ON_MOVE be treated the same as TOOL_NONE when installing or
removing a part. Other properties of UNMOUNT_ON_MOVE unchanged
reduced difficulty of install of storage battery