mep-player.js: add option (setDimensions) to disable the setting of widths and heights through JS, since there was no way to have a fluid player width and height (i.e. set to 100% each)
mep-player.js: move option `setDimensions` into function `setPlayerSize()`
Merge pull request #1236 from votum/setDimensionsOption

Option `setDimensions` to allow deactivation of inline widths and heights at player elements