Removed ES6 compiler test pages from version tracking.

Since these are not public-facing, take a good while to re-compile, and make more complicated diffs, there's little reason to keep them tracked.
Fixed build.js to create the compilers directory.

Also, it will no longer build the compiler pages without the new "compilers" command-line argument.
Added TypeScript column.

TS only supports a few things right now, but they're there. Note: TS fails all of the class tests because it doesn't allow classes declared anywhere other than module top-level.
Forgot to add skeleton.html.
Updated 6to5 and Traceur results.
Merge pull request #340 from webbedspace/6to5

Updated 6to5 and Traceur results
Merge pull request #312 from webbedspace/typescript

Added TypeScript column
Merge pull request #339 from webbedspace/compilers

Removed ES6 compiler test pages from version tracking