Added "Month to Date" Time Frame Option

Modified strings.xml to add "Month to Date" String (No translations sorry)
Modified charts_menu.xml files to Add "Month to Date" Option
Modified Prefernces.java to add "MONTH_TO_DATE" to Timeframe enum
Modified BaseChartActivity.java to include "MONTH_TO_DATE" in onCreateOptionsMenu() and onOptionsItemSelected(). Copied the functionality of the other options (Note: I've re-wrote and recommited BaseChartActivity.java several times now, and every time I commit on the local github client, it displays just the lines I've changed and once I sync back to GitHub it trashes that and just says I've changed the entire file *Grumble* Its doing my nut...)
Modified ContentAdapter.java to include "MONTH_TO_DATE" to getAdmobStats() and getStatsForApp(). Using Calendar.getInstance().get(Calendar.DAY_OF_MONTH); to grab the day of the month to set again the limit.