i-bem.bemhtml: use the same object for this.mods and this.ctx.mods

[narqo]

use

mods : vBlock? this.ctx.mods || (this.ctx.mods = {}) : this.mods

in i-bem.bemhtml

This will allow us to change mods object within default mod so this changes will reflect node's HTML-classes:

block('b1')(
  default()(function() {
    this.mods.a = 'b';
    applyNext();
  }),
  mod('a', 'b')(function() { return 'beep' })
)

// <div class="b1 b1_a_b">beep</div>