GAP.jl 0.3.4 released

Today GAP.jl 0.3.4 has been released.

Diff since v0.3.3

Closed issues:

• Sometimes GAP is started multiple times from Julia (#333)
• Document the release process of this package (#352)

Merged pull requests:

• suppress the GAP banner when importing GAP.jl (#342) (@ThomasBreuer)
• Get rid of __GAPINTERNAL_LOADED_FROM_GAP (#368) (@fingolfin)