commit 052483efc6df8351e3def84e674c47b2b5dd4dc2
author Asim Shankar <ashankar@google.com> Mon Sep 22 19:59:34 2014 -0700
committer Asim Shankar <ashankar@google.com> Mon Sep 22 19:59:35 2014 -0700
tree 0f52abca596d408f6e31aec9833f2f51eb0be604
parent 021b949d20b4fb9ca984e633452e77786ccf0bf8

veyron2/security: Implementation of a public-key signature based ThirdPartyCaveat.

This commit includes:
- VDL specification of the ThirdPartyCaveat and corresponding discharge
- Factory function for creating ThirdPartyCaveats
- Principal.MintDischarge for creating Discharges

Miscellaneous:
- veyron/security/caveat package is now removed
- Added a "String" method to the Caveat type to print out useful information
- Renamed "UnconstrainedDelegation" to "UnconstrainedUse" since this "Caveat"
  can apply to both blessings and discharges.
- Renamed "contentHash" to "digest" to comply with more commonly used
  terminology ("message digest" or "digest")

Change-Id: I0ccce2557b4c3c5cba0c3cc7acba62b8dc118339