Add draft and confidential admonitions
The admonitions are each controlled by separate attributes; `public`
disables the confidential admonition and `release` disables the draft
admonition. These can be set on the command-line by passing `-a public`
or `-a release`, respectively, though the build currently never sets
these attributes.
= TBTC: A Decentralized Redeemable BTC-backed ERC-20 Token
+ifndef::release[]
+.DRAFT
+****
+NOTE: This document is a rough draft. The contents may be inaccurate, not fully
+fleshed out, and are certainly not final.
+****
+endif::[]
+
+ifndef::public[]
+.CONFIDENTIAL
+****
+WARNING: This document is currently CONFIDENTIAL. Sharing with anyone without
+the express authorization of Keep SEZC is not permitted.
+****
+endif::[]
+
toc::[]
[abstract]
