v0.156: Grog machines & Flama boss fight track

-We added a first version of the Flama boss fight music track. Still has to be edited and tweaked, but to have it playable will help us to get related feedback. So please send us related, specific and constructive feedback.

-Updated the artwork of the drink vending machines: now they have a "Grog" banner, as suggested.

-Intro texts are drawn faster, so they are shown during a longer period of time. This should make them a bit easier to read.

-Added a new sound fx for the gatling minigun that appears in the bonus Survival mode.

-Several minor fixes and tweaks.

Known issue: When punching Flama while he is in the floor sometimes you dissapear temporally.