[TIMOB-3386] Android: Write to File in Append Mode

You cannot use MODE_APPEND to set the write mode to append when writing to a file, despite the properties listed in [Titanium.Filesystem](http://developer.appcelerator.com/apidoc/mobile/latest/Titanium.Filesystem-module). MODE_APPEND is not demonstrated anywhere in the KitchenSink - have raised ticket TIMOB-4212 to address. In Android only, you can pass a boolean to write() to use append mode, as in the example below, but this is not documented.

var newFile = Titanium.Filesystem.getFile(Titanium.Filesystem.applicationDataDirectory,'newfile.txt');
newFile.write('line 1\n');
newFile.write('line 2\n', true);

Ti.API.info('newfile: '+newFile.read());</code>

Ticket TIMOB-4213 has been raised to address this APIDoc issue. Associated Helpdesk Ticket: [http://developer.appcelerator.com/helpdesk/view/76562] Remaining on this ticket: * determine whether the write() boolean argument and/or MODE_APPEND should work on each platforms, and test to ensure that they are in parity