Merge pull request #4 from sebastientromp/unity_46_ui

Unity 46 ui
Add basic enemy attack + flash white (color is customizable) when attacking
Added flashing animations when enemy or player takes damage
Added "Radius" property to skills
Fixed the display of floating point numbers to display only 1 decimal digit
Changed the scale of player health / mana (x10) to be able to show variations without having to use decimal point numbers
Reworked the way "number of uses" was handled to fix: NumberOfUses carries over each iteration
Fixed bug where parent selection changed the order of the skills for the player in the next level
* Solution is a bit cumbersome, as it involves making the saved data immutable (making it a property), thus making it unavaiable in the inspector for tweaking.

Renamed some prefabs to have names that are easier to handle
* Wave generation now use a Settings class to easily switch between Dev and Prod
* Added a slight random to enemy firing time
Now clicking directly on a skill will display the skill attributes
Reworked the end-level screen (factored skills, used the SkillDetails to display info)
Fixed a couple of bugs caused by previous commit, where the skill wouldn't fire properly anymore
Merge pull request #5 from sebastientromp/unity_46_ui

Unity 46 ui
"Arena" on which the action takes place, materialized by two different textures (one for the background, and one for the arena)
Enemies spawn inside the arena
Merge pull request #12 from sebastientromp/unity_46_ui

"Arena" on which the action takes place, materialized by two different t...
Fixed issue #13 - now using the SkillBarItem object to distinguish between selected skills
Fix bug where boss would not appear within the arena's bounds (issue #10)
Player can now choose what slot in the skill bar the new skill should take (issue #15)
Behavior of the "help" is a bit strange, and will need to be corrected
Added a text with the current level
Added game over screen
Basic save / load mechanism
Can choose name and image for new skills
Improved saving / loading to work on Web Player as well
Added dropbox public URL to test the game
Merge pull request #16 from sebastientromp/unity_46_ui

This is getting too big, reviewing all the changeset will prove difficult
Tweaking a bit the player attack speed. Today, it's way too fast for a first level. Maybe it could go faster over time, or rather with specific skills that temporarily boost the attack speed for instance