Update spirit from develop.
Update geometry from develop.
Update geometry from develop.
Update geometry from develop.
Update predef from develop.
Update predef from develop.
Update predef from develop.
Update spirit from develop.
Update spirit from develop.
Update config from develop.
Update date_time, functional from develop.
Update thread from develop.
Update detail, utility from develop.
Update utility, system from develop.
Add module core
Update core, atomic from develop.
Update core from develop.
Add core to libraries.htm, maintainers.txt.
Add core to status/Jamfile.v2
Update utility from develop.