MAGN-4376: Long names need to be truncated

# Preface
Not only class buttons titles must be truncated,but also method buttons titles.
# Before
![image](https://cloud.githubusercontent.com/assets/8158404/4289789/9a711028-3db6-11e4-8518-e8e8e22fe1df.png)
# After
![image](https://cloud.githubusercontent.com/assets/8158404/4289755/5a282858-3db6-11e4-96d5-a5f21a6155b9.png)
# Note
We need to check width of parent element. And show more or less characters of title.
E.g.
![image](https://cloud.githubusercontent.com/assets/8158404/4289812/d8250ee2-3db6-11e4-9bfe-e6220b0537cc.png)
![image](https://cloud.githubusercontent.com/assets/8158404/4289815/deb01a54-3db6-11e4-99b8-fa7fa95b0c2e.png)
# Reviewers
@Benglin,@vmoyseenko, please take a look.

Link to YouTrack:
[MAGN-4376 Long names need to be truncated](http://adsk-oss.myjetbrains.com/youtrack/issue/MAGN-4376)

P.S. Truncation done only for primary members!
I know, what you would say: it's bad to give itself to converter.
I tried this thing:
``` c#
<TextBlock.Text>
                                    <MultiBinding Converter="{StaticResource MethodNameToDisplayConvertor}">
                                        <Binding Path="Name" />
                                        <Binding Path="ActualWidth"
                                                 RelativeSource="{RelativeSource Mode=FindAncestor, AncestorType=search:SearchView}" /> 
                                    </MultiBinding>
                                </TextBlock.Text>
```
But it throws null exception.