Isolate the usages of SPI Fly dynamic weaving.

The play, pause, and stop methods all work as expected from both the GUI
and the Gogo Shell using the command line. The problem I'm trying to solve
is strictly related to the load method. The load method works as expected
when executed from the Gogo Shell using the command line, but does not
work as expected when executed from the GUI.

The purpose of this commit is to isolate the functionality that is causing
the load method to fail from the GUI, specifically, to isolate the integration
with the Apache Aries SPI Fly dynamic weaving capability. This commit makes
it possible to configure turning this functionality on or off. If dynamic
weaving is disabled, the load method works as expected from both the GUI
and the Gogo Shell using the command line. If dynamic weaving is enabled
the load method fails when executed from the GUI but succeeds when executed
from the command line.

Obviously disabling dynamic weaving is equivalent to disabling audio when
the Media Player is playing because dynamic weaving is required within the
OSGi container to play an MP3 file.

The problem is located in MP3Player on line 124:

    '''java

    temp = (SourceDataLine) AudioSystem.getLine(info);

    '''

When dynamic weaving is enabled this line will execute successfully when
executed with the following command line in the Gogo Shell:

    '''shell

    mp3:load [path_to_mp3_file]

    '''

The argument `path_to_mp3_file` should be the canonical path to the mp3 file
and should be wrapped in quote marks. For example if there was test.mp3 file
located in a folder called music in the user's home directory then the command
would look like this when run in a *nix OS:

    '''shell

    mp3:load "/home/user/music/test.mp3"

    '''

But it will fail with the following error when executed from the GUI:

    '''text

    java.lang.IllegalArgumentException: No line matching interface SourceDataLine supporting format PCM_SIGNED 44100.0 Hz, 16 bit, stereo, 4 bytes/frame, little-endian is supported.
      at javax.sound.sampled.AudioSystem.getLine(AudioSystem.java:479)
      at com.github.axiopisty.plarpebu.mediaplayer.mp3.provider.internal.MP3Player$MP3Reader.<init>(MP3Player.java:124)

    '''

I'm trying to figure out how to fix this so the load method will work
from the GUI too. But I'm going to need help from an OSGi expert because
this is beyond my current scope of knowledge.