implement the remainder of hate.filesystem

[shakesoda]

Currently missing:

filesystem.createDirectory() filesystem.getAppdataDirectory() filesystem.getIdentity() filesystem.getUserDirectory() filesystem.lines() filesystem.load() filesystem.newFile() filesystem.newFileData() filesystem.setIdentity() filesystem.setSource()

Also worth noting that the current functions need testing to verify that they are properly behaved - at the very least, getWorkingDirectory() is spitting out "."