update file I/O

[ionab10]

Creates RankGrapher directory if doesn't exist to address #4

Adds timestamp (in epoch seconds) and playlist number to data.csv entries

Adds header row to data.csv:
game_number,match_guid,mmr,session_number,playlist,timestamp,goals,assists,saves,demos,shots,score,mvp,win

Tracks all casual playlists in 0data.csv since all casual playlists share the same MMR

goals,assists,saves,demos,shots,score,mvp,win stats currently set to 0 and are unused

[adamgerhant]

Is there any reason to save all the additional statistics if they cannot be displayed? It would increase the file size considerably. It also has to be backwards compatible.