Building base material undump script.

Based on an idea in https://github.com/peterix/dfhack/issues/119
Better way to check for the contained_items field.
Ignore Mac OS X .DS_Store files
New plugin: building-hacks. Allows workshops to block liquids and consume mechanical power, connect to machines.
Added animation and on update callback.
building-hacks: added lua convenience function, made impassible tile fix optional.
eventful: added support for custom workshops and a convenience function to interpose side panel generation
docs: updated eventful lua api and added building-hacks docs.
Minimal Readme documentation for the undump-buildings command
gm-editor: Added enum printing and selection.
gm-editor: a bugfix for some entries not having fields
gui/gm-editor: Fixed enum editing. And added free pointer/reinterpret options
Merge gm-editor changes by warmist into develop
Show box select dimensions in Automaterial
Update uicommon.h with new common display functions
autotrade: adds "(Un)mark All" options to both panes of trade screen.
mousequery: several usability improvements.
mousequery: show live overlay (in menu area) of what's on the tile under the mouse cursor.
Add workshop profile search.
Use shifted keys for buildingplan so as not to interfere with QuickFort.
dwarfmonitor: add screen to summarise preferences of fortress dwarfs.
getplants: add autochop function to automate woodcutting.