[age restriction] progress 14/n - withdraw and deposit

Age restriction support for
  - withdraw is done and tested
  - deposit is done and tested

TODOs:
  - melt/refresh/reveal
  - link

------

Added functions
 - TALER_age_restriction_commit
 - TALER_age_commitment_derive
 - TALER_age_commitment_hash
 - TALER_age_restriction_commitment_free_inside
 - Hash of age commitment passed around API boundaries

Exchangedb adjustments for denominations
 - all prepared statements re: denominations now handle age_mask
 - signature parameters adjusted

Hash and signature verification of /keys adjusted
 - Hashes of (normal) denominations and age-restricted denominations are
   calculated seperately
 - The hash of the age-restricted ones will then be added to the other
   hash
 - The total hash is signed/verified

Tests for withdraw with age restriction added
 - TALER_EXCHANGE_DenomPublickey now carries age_mask
 - TALER_TESTING_cmd_withdraw_amount* takes age parameter
 - TALER_TESTING_find_pk takes boolean age_restricted
 - WithdrawState carries age_commitment and its hash
 - withdraw_run derives new age commitment, if applicable
 - Added age parameter to testing (13 as example)

Various Fixes and changes
 - Fixes of post handler for /management/extensions
 - Fixes for offline tool extensions signing
 - Slight refactoring of extensions
 - Age restriction extension simplified
   - config is now global to extension
   - added global TEH_age_restriction_enabled and TEH_age_mask in
     taler-exchange-httpd
   - helper functions and macros introduced

1 files changed, 13 insertions, 0 deletions

diff --git a/src/lib/exchange_api_refresh_common.h b/src/lib/exchange_api_refresh_common.h
index ab19ad7d1..b6926b51f 100644
--- a/src/lib/exchange_api_refresh_common.h
+++ b/src/lib/exchange_api_refresh_common.h
@@ -53,6 +53,12 @@ struct MeltedCoin
   struct TALER_Amount original_value;
 
   /**
+   * The original age commitment hash.  MUST be all zeroes, if no age
+   * commitment was set.
+   */
+  struct TALER_AgeCommitmentHash h_age_commitment;
+
+  /**
    * Timestamp indicating when coins of this denomination become invalid.
    */
   struct GNUNET_TIME_Timestamp expire_deposit;
@@ -93,6 +99,13 @@ struct FreshCoinData
   struct TALER_CoinSpendPrivateKeyP coin_priv;
 
   /**
+   * Arrays age commitments to be created, one for each cut-and-choose
+   * dimension.  The entries in each list might be NULL and indicate no age
+   * commitment/restriction on the particular coin.
+   */
+  struct TALER_AgeCommitment *age_commitment[TALER_CNC_KAPPA];
+
+  /**
    * Blinding key secrets for the coins, depending on the
    * cut-and-choose.
    */