M - The current Midas context

The current Midas context (M):

Handles input and output.

Usually used for output from the primitive:

`M.info(<string>)`	Writes out "INFO:" string to the terminal.
`M.warning(<string>)`	Writes out "WARN:" string to the terminal.
`M.error(<string>)`	Writes out "ERROR:" string to the terminal and aborts.

Also used as the reference context when opening a file.
```
new DataFile(M, <fileName>)
```
It is important to use the above methods in place of System.out.println(...) since the NeXtMidas methods handle special cases where output may need to be temporarily redirected.

Something very cool:
- In Java everything is string-able. This allows anything to be concatenated to a string using a plus sign (+). For example:
```
double freq = ...;
String user = ...;
Table  conf = ...;
...
M.info("MYPRIM: Setting freq="+freq+" user="+user+" config="+conf);
```

Java Experts Take Note:
Calling `M.error(<string>)` is intended to make things easier for those new to Java. It is very similar to throwing `new MidasException(<string>)`. Those familiar with Java should throw the exception, as that enables the normal Java code-path checking.