add(build_toolchains): New command to build cross and native target toolchains.

This replaces the cross-toolchain compile step in bootstrap_sdk and adds the
ability to build native toolchains using the cross toolchain. This is just
the first step towards actually providing the native toolchain in a container.
fix(common.sh): Stop collecting stats and uploading them to Google.

Just... no.. in so many ways. Kinda dumb it took me this long to delete
this little chunk of rather annoying code.
fix(build_toolchains): Remove hard-coded portage profile
fix(build_toolchains): Fix simple logging typo
fix(catalyst_toolchains.sh): Fix error in doc comment
Merge pull request #126 from marineam/turtle-chain

Turtle chain