Use the techtree translation key: `TagName_<actual name of tag>`.
Eg, `TagName_warrior` for units that have `<tag name="warrior" />`.
As with the rest of techtrees, the game setting "Allow translated
techtrees" must be enabled (otherwise reasonable defaults are shown).

Also, the TagDesc is now translated for upgrades, too. This makes
everything related to tags translatable.

IMPORTANT: Requires adding the following to the English lang file:

    TagDesc=Tag:

I think I goofed this commit and part of the change is in the prior
commit, which probably won't build because of this.

Issue was returning by value was creating a copy of a set instead
of returning a reference (which was what I expected).

Note: not yet translated.

Also fixed awful crash that occured due to how isAffected was
implemented. Fix is rather unusual, but works.

Note that only the application of tags is complete. Display and
load/save still to come.

Also fixed bad null pointer bug that was freezing the game when you
hover over the upgrade button.

This prevents duplicate units (easy to do if you have multiple,
overlapping tags). This also cleans up the code (the previous
method of checking for duplicates was a bit messy).

Ensures uniqueness of units. Only applies to attack boosts (regular
upgrades are next). Requires changing how the set is accessed, since
set has different methods than vector.

Not yet available for attack boosts.

…nemy

Feature/spawnattack at enemy

…ojectile arrives at the targetpos.

Unit will always try to attack if it has an attack command.
Unit attacks the target POS and not the target UNIT of the attacker.

…ether the unit spawns at the target or at the attacker.

In Addition i changed the command which is given to the spawned unit to an attack command on the target cell.
( I think this makes way more sense than giving a move command to the meeting point)
( This also works if the spawned does not have a attack command. It will move to the enemy then)

…t-source into develop

…develop

Also renamed loss-value accordingly. As discussed with Titi in IRC.

all given damage percents from the projectiles must sum up to exactly 100%

multiple sounds timed sounds for all skills. 
By this you can now play a sound for shooting every single shot too.