Force gas giants to have some visible atmosphere

Workaround small scale heights for gas giants by increasing them
slightly. Increase gas giant temperatures in the 0 temperature
workaround.
init custom system atmosphere density to 0, and temp to 1K
Updated Xcode project
version bumps for 33 freeze
version bumps for alpha 34 dev
fix Lua console so that it lets you continue incomplete commands

It was always supposed to do this, but at some point (probably the
switch to Lua 5.2) it stopped working. If return is pressed when the
current command is syntactically incomplete, it will insert a newline
and let you continue the command (instead of giving an error message)