Implemented cookie-based authentication to the API.

Created timestamper module to start the application.
Added cookie-based authentication to ts_api.
Added utility methods to ts_api:
    * make_json_400/1 and make_json_400/1
    * make_json_401/1 and make_json_401/2
    * parse_json_body/1 reads a JSON object from a HTTP request body.
Implemented ts_api_session module to manage api user sessions.
Fixed ts_entry:list* methods to be 0-indexed.
Removed the ts_json:ejson_to_record/1 implementation for ts_user records.
    Decided that ts_user records are never trusted from the client,
    manipulation of fields such as pwd, username will be restricted to
    app pages.
Changed the password hashing algorithm. Now uses SHA1(pwd + 256bit salt).
    Want to use bcrypt, investingating cross-platform bcrypt implementation.
Fixed yaws.conf config file.

src/timestamper.erl

@@ -0,0 +1,16 @@
+-module(timestamper).
+-export([start/0, create_tables/1]).
+
+start() ->
+    ok = application:load(mnesia),
+    ok = application:set_env(mnesia, dir, "/home/jdbernard/projects/timestamper/web-app/db/test"),
+    ok = mnesia:start(),
+    ok.
+
+create_tables(Nodes) ->
+    TableOpts = [{disc_copies, Nodes}],
+    {atomic, ok} = id_counter:create_table(TableOpts),
+    {atomic, ok} = ts_user:create_table(TableOpts),
+    {atomic, ok} = ts_timeline:create_table(TableOpts),
+    {atmoic, ok} = ts_entry:create_table(TableOpts),
+    ok.