Merged TechVisible functions.

git-svn-id: svn://svn.code.sf.net/p/freeorion/code/trunk@7568 dbd5520b-6a0a-0410-a553-f54834df5b05
Set up double-clicking a saved design to load it into the main design panel.

git-svn-id: svn://svn.code.sf.net/p/freeorion/code/trunk@7569 dbd5520b-6a0a-0410-a553-f54834df5b05
Grooming / splitting of parsers to hopefully reduce compile memory use.

git-svn-id: svn://svn.code.sf.net/p/freeorion/code/trunk@7570 dbd5520b-6a0a-0410-a553-f54834df5b05