Fixed issue #1361 added command-line support for Android mode

I added `processing.mode.android.Commander`, which can be used for Android command-line build.
And here's the corresponding shell-script: `build/linux/processing-android`. It is the same as `processing-java` but calls another class at the end.
```
Command line edition for Processing 0217 (Android Mode)

--help               Show this help text. Congratulations.

--sketch=<name>      Specify the sketch folder (required)
--output=<name>      Specify the output folder (required and
                     cannot be the same as the sketch folder.)

--force              The sketch will not build if the output
                     folder already exists, because the contents
                     will be replaced. This option erases the
                     folder first. Use with extreme caution!

--target=<target>    "debug" or "release" target.
                     "debug" by default.
--build              Preprocess and compile a sketch into .apk file.
--run=<d|e>          Preprocess, compile, and run a sketch on device
                     or emulator. Device will be used by default.

--export             Export an application.
```


Moreover, I created a more generic version of command-line processing:
`processing.app.Commander` class can be used to run `processing.mode.***.Commander` class from the corresponding mode.
`build/linux/processing-cli` is the new command-line shell script, which uses `processing.app.Commander` to launch `java` or `android` command-line mode.

Here's `processing-cli` usage:
```
pif@pif: $ ./processing-cli
Command line front-end for Processing.
First argument is the mode, which should be launched.

ONLY 'java' and 'android' modes are supported.

Usage: 
./processing-cli java --sketch=...
./processing-cli android --sketch=...
```