FilePlayer calls onBuffer when "waiting" is fired

[me-andre]

Introduces support of onBuffer callback to the FilePlayer

[cookpete]

This has already been discussed before: #74. The waiting event seems too buggy to rely on for onBuffer, especially if onPlay is then not called when playing is resumed.

There is a getInternalPlayer() instance method if you want to set this in your own implementation.

[me-andre]

I definitely agree.
Not firing onPlay after "waiting" can badly break things, as it did to my app.
This is what is fixed by #612

[me-andre]

Closing in favor of #615

[NahidAhmed07]

how to change buffer spinner color. Its default color is white.