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
scripts/digfort: better csv handling
digfort: add start() comment
Update "plants" plugin

* Add "createplant" command, creates a shrub or sapling at the cursor.
* Put help text in command definitions so CR_WRONG_USAGE works properly
Missed parameter in plugin command init
Update plugins to use CR_WRONG_USAGE where appropriate
plants: move all commands as "plant" subcommands, update NEWS/Readme
Use df::allocate here for proper compatibility with 40d and earlier
MaterialInfo: fix decoding for COAL subtypes
Fix wrong argument iteration bounds in dfhack.matinfo.find().
Get rid of the std exception.
Hide fake historical figures from legends xml export.
Merge branch 'master' of git://github.com/angavrilov/dfhack
Update Compatibility section

OS X has been supported since 0.34.11r3
Merge branch 'master' of github.com/quietust/dfhack
compile.rst: add a note on VS2010 SP1
Enhance createitem, can now place items into containers or buildings
A bit of cleanup