Add embark-tools

A collection of embark-related tools (currently implementations of
embark anywhere and nano embark)
Update Readme.rst
Add sand indicator and allow enabling/disabling all tools
Update readme
Fix crash with child screens (e.g. saving a macro)
Add sticky (equivalent of tweak stable-cursor)
Display embark label on all 5 map pages
sticky: Fix handling of rapid input
Fix embark sidebar updating
Add embark-tools settings interface
New tweak: confirm-embark

Adds a confirmation when selecting [e]mbark on the "prepare carefully" screen.
Suggested in multiple threads on forums.
tweak confirm-embark fixes

* Added a display of the total embark points remaining, for convenience
* Made 'esc' work by interposing key_conflict as well
* Rearranged to look more like DF's confirmations
confirm-embark: Make esc work again
Use INTERPOSE_NEXT in key_conflict

See comment on 0a1d87c09f418c8c9075083bb207d91c6185628d
Implement runCommand in Lua API
Add dfhack.run_command (Lua)

Simplified version of runCommand
Util method (in the Units class) to get a unit squad name (the translated name, or alias if set)
Squad column and squad info in Dwarf Manipulator (manipulator plugin)
Update documentation related to Dwarf Manipulator's squad column
Merge branch 'develop' into dev-embarktools-pr