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 lua-runcommand
Lua runCommand improvements

* Return error codes (e.g. CR_FAILURE) when a command fails instead of output
* Make dfhack.runCommand() take a list of arguments as well
Fix runCommand crash, return output and result
Use squad::find instead of indexing the vector
Allow to toggle between Profession and Squad view instead of wasting screen space with a new column
Update the Dwarf Manipulator documentation section according to the last change (toggle between Profession and Squad view)
Update NEWS
Allow runCommand arguments to be passed as a table internally
Handle invalid arguments to runCommand
Merge branch 'lua-runcommand' of git://github.com/lethosor/dfhack into develop
Erase remnants of the window frame and recompress screenshots with pngout.
Merge branch 'manipulator_show_squad' from git://github.com/pierredavidbelanger/dfhack.git into develop
Rebuild Readme.html.