NINJA_STATUS now takes %e for elapsed time.
Made %e purely a number.
Add compdb tool

This tool helps convert Ninja build files to a compilation database
of the form used by Clang tooling.
Merge pull request #512 from pcc/compilation-database

Add compdb tool
Added %e to manual.asciidoc, fixed brace style.
Merge pull request #513 from fifoforlifo/master

Adding elapsed time (%e) to NINJA_STATUS.