RocketInfo font size now configurable in option.  Small is 11, medium is 14, large is 17.

Corrected spelling on PrefChoiseSelector name, will get the translation keys some other time.
Added LineMetrics.descent to the line height for laying out the text in RocketInfo.
This is a simple change to help out the Mac Crowd.  It just changes the name of Startup to OpenRocket so the the menu bar says OpenRocket instead of Startup.

This gets around the very fragile OS X setup thing we have trying and failing at with the mac java client
Changed startup class to OpenRocket
Merge pull request #217 from enderw88/Change-Startup-OpenRocket

Really fix Mac menu name issue.
Merge pull request #216 from enderw88/Configure-design-window-font-size

RocketInfo font size now configurable in options.