Add ability to pause and continue recording

[robinsmidsrod]

In our particular use of FlashWavRecorder we could really need the a feature for pausing the recording and then continue it.

Use-case: Our users usually listen to another recording, pause that playback, record a bit, pause the recording, play back a bit more of the original recording, pause playback, record a bit more and so forth.

We've been using another recording component until now, and this is the last feature we could really need, to get rid of that recorder (which is based on a Java applet).