Don't process --game_data if its value is empty

Closes #418
Merge pull request #437 from dorkster/bugfixes

Don't process --game_data if its value is empty
Ignore speed effects when adding hero power cooldowns
Merge pull request #439 from dorkster/bugfixes

Ignore speed effects when adding hero power cooldowns
Added cooldown_hit to statblock, prevents players & enemies from being stunlocked due to fast/consecutive hits pushing them into the on hit animation.
Moved enemy sfx_hit out of block testing against hit cooldown
Corrected initial loaded values for cooldown_hit so that the ticks started at appropriately at zero
Configurable restyled NPC dialogs
Merge pull request #442 from josephbleau/hit_cooldown

Added cooldown_hit to statblock, prevents players & enemies from being stunlocked due to fast/consecutive hits pushing them into the on hit animation.
Merge pull request #444 from dorkster/npc_dialog

Configurable restyled NPC dialogs
Calculate bonus per base stat in one place
Add bonus absorb per defense
Remove recalc_alt() from applyEquipment()
Merge pull request #450 from dorkster/bugfixes

Remove recalc_alt() from applyEquipment()
Fix coloring of 'Requires Power' in power tooltips
Merge pull request #451 from dorkster/bugfixes

Fix coloring of 'Requires Power' in power tooltips
Don't invalidate vector iterator
Status-based trader stocks

Closes #452
Merge pull request #455 from dorkster/npc_stock

Status-based trader stocks
Merge pull request #453 from igorko/master

Fix events iterator invalidating
Merge pull request #449 from hean01/master

Fix issue were sound volume always was initialized to zero.