Pypo fixes and improvements

General:
 * Moved pypo author info into one file
 * Added two database columns in schedule table: "schedule_group_played"
   and "media_item_played".

API clients:
 * Created get_liquidsoap_data() function which allows you
   to give arbitrary data to liquidsoap.
 * Added documentation
 * Renamed functions to make it more obvious what is happening

pypo_cli:
 * Got rid of more constants that were not needed
 * Created function set_export_source() to reduce code repetition
 * Separated the downloading of the schedule from tracking what has
   been played.  The tracking info is now kept in a separate file.
   This fixes the major bug that the playlist keeps restarting for
   the first minute of playback.
 * converted more print statements to debug statements

pypoTester:
 * Now uses samples from the audio_samples directory, and schedules two
   audio clips back-to-back.

backend/propel-db/build/sql/schema.sql

@@ -244,6 +244,8 @@ CREATE TABLE "cc_schedule"
 	"fade_out" TIME default '00:00:00',
 	"cue_in" TIME default '00:00:00',
 	"cue_out" TIME default '00:00:00',
+	"schedule_group_played" BOOLEAN default 'f',
+	"media_item_played" BOOLEAN default 'f',
 	PRIMARY KEY ("id")
 );
 

backend/propel-db/schema.xml

@@ -182,6 +182,8 @@
     <column name="fade_out" phpName="FadeOut" type="TIME" required="false" defaultValue="00:00:00"/>
     <column name="cue_in" phpName="CueIn" type="TIME" required="false" defaultValue="00:00:00"/>
     <column name="cue_out" phpName="CueOut" type="TIME" required="false" defaultValue="00:00:00"/>
+    <column name="schedule_group_played" phpName="ScheduleGroupPlayed" type="BOOLEAN" required="false" defaultValue="0"/>
+    <column name="media_item_played" phpName="MediaItemPlayed" type="BOOLEAN" required="false" defaultValue="0"/>
   </table>
   <table name="cc_sess" phpName="CcSess">
     <column name="sessid" phpName="Sessid" type="CHAR" size="32" primaryKey="true" required="true"/>