made ship prefabs
Revert "made ship prefabs"

This reverts commit 9c474a31d7997fe0a8a20b4c4a0664fb6b4681a1.
Can choose between different ships

No functional difference yet
Fixed can't change ship
Change bad guys to sparrow
branch merge - can now choose ship

Enemy ships also look different
Updated menu and enemy
add currency and shop button
ships now have different attributes
Merge remote-tracking branch 'origin/master' into space-junk