Assorted module issues from recent changes

[Cervator]

Edit: Updated quite a bit

I figure these relate to the replacement of the embedded module system with gestalt-module - little unsure whether the bug is here or if this should be in the gestalt-module tracker :-)

• Selecting a module where Core exists somewhere down the chain makes Core highlight yellow instead of green (gets selected as a dependency instead of mandatory module) - should be worked via Game Modes - redux #689
• De-selecting a module where Core exists as a downstream dependency also de-selects Core - should be worked via Game Modes - redux #689
• Disable all can disable Core (should be forced on, at least for now) - should be worked via Game Modes - redux #689
• Indirectly selected (yellow) modules appear unable to scan for / register world generators (like enabling Throughout the Ages 2 where the world gen is in 1) - scan active module set (including dependencies) rather than only explicitly selected modules for world generators
• A module with module.info instead of module.txt (Rails) isn't showing up in the module list - unsure if that's because of the scanning or if Gradle tweaked to expect .info instead of .txt isn't building it right (has compiled classes though) - will try to handle this via Apply updated module template all over Nanoware/Terasology#61
• Module list is no longer alpha-sorted

Otherwise looks pretty stable, running my local integration workspace with all stable modules present!

Some of the fixes are probably easy but figuring best to leave for @immortius :-)

[immortius]

I decided not to make core mandatory, which explains the first 3.

The forth is because the filtering of world generators is not based on the current dependency set, but by directly checking whether a world generator is in a selected module. This should be changed so that WorldGeneratorManager is scans the current module set after it is changed.

Terasology specifically overrides the module file name to module.txt (for compatability), so module.info shouldn't work. The .info extension is more for future users of gestalt-module.

Fixed the last one.

[Cervator]

Updated top post - two big parts split out, leaving just the world gen scanning thing. Thanks for clarifications :-)

[msteiger]

I think that the last bullet point is fixed now. Did you intend to leave # 4 open, @Cervator ?

[Cervator]

Yeah the fourth item is still valid. I went ahead and split it out into a better named issue - closing this :-)