Searching by wikis, steam and forums I've found these results:

Attributes (Strength, Dexterity, etc)
Level 1 .............5
Each even level ....1

Abilities (Willpower, Armor Specialist, etc)
Level 1 ..........5
Levels 2-5 .......1
Levels 6-10 ......2
Levels 11-20 ....3

Talents (Bully, Escapist, etc)
Level 1 .................2
At level 3 ..............1
And every 4 levels ....1

So at level 20 you obtain
15 Attribute points (16 with Bigger and Better talent)
49 Ability Points (68 with Lone Wolf talent)
7 Talent Points

Also this is the complete list of skills
http://divinity.gamepedia.com/Skills


The only thing that it seems essential to plan a character is the maximum points that can be spent:

For Attributes I think the maximum is 10 or 12 for each one.
For Abilities I think the maximum is 5 points for each one.
For Talents must be only 1 point each one.
And all of them can grow with boosts (gear, etc).

Please someone confirm.