Speed up rendering by having easier Renderable sort functions.
Avatar rendering layers at runtime using the animation classes.

* changing items speed up.
* player related images are independant of each other because of
  separate animation definition files, images can be shrinked.
* API change: the file engine/hero_options.txt is different now:
  the layer order is defined per direction in a oneliner:

  # layer=direction, list of layers.
  layer=0,main,body,head,off
  layer=4,off,body,head,main
Fix hero not being visible at startup of maps.
Animation: remove unused sprites variable.
Remove most warnings of static code analysis.

The style warnings found with
cppcheck --enable=all src/ 2>&1 |grep style
have all been removed.

Also many file reading functions got a short return if the file was not
to be opened. The short return allows to have the actual parsing stuff
on one less indentation level.

Actual warnings found with
cppcheck --enable=all src/ 2>&1 |grep warning
have mostly been removed. Some still remain.
Merge pull request #36 from SBasalaev/master

Russian translation for engine
Merge pull request #37 from SBasalaev/master

More on Russian translation
Ignore left-click inside MenuCharacter area
Merge pull request #38 from igorko/master

Ignore left-click inside MenuCharacter area
Don't clear and re-fill character stat list every frame
Merge pull request #39 from dorkster/bugfixes

Don't clear and re-fill character stat list every frame
Only refresh MenuCharacter when stats change
Merge pull request #40 from dorkster/bugfixes

Only refresh MenuCharacter when stats change
Italian engine language update by dallatower
Merge branch 'master' into avatar
Don't translate internal names for elements
Merge pull request #41 from dorkster/bugfixes

Don't translate internal names for elements
Adding credits to fileheaders.

As walking through the git history and checking if each of the commit
is worth the credits attribution, I just set the line to 20 changed lines
(counted the git way, 10 changed lines are 10 lines removed and
10 lines added, hence qualify.)

bash magic:
> git log --stat --author=stefanbeller |grep "|" |sort | awk '$3>20;'|awk '{print $1}' |uniq
Merge remote-tracking branch 'mainline/master' into avatar
Translate resist string when displayed instead of when loaded