company-pseudo-tooltip-edit: update company-width

#138
Indicate current candidate's backend when it's in a group

Closes #109
adding a simple sorter to keep completions of length 1 as first completions
company-update-group-lighter: privatize
Define company-sort-by-backend-importance

Closes #110
Improve comment wording
Don't assign to company-point in company-abort and company-finish

* Closes #143

* Rename `company-begin' to `company--perform'.

* Drop `company-begin-commands' checks from `company--should-complete', they
  should be satisfied at that point already.

* When creating timer, replace company-point comparison check with disallowing
  this-command to come from company- namespace.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	company.el