Do not define a variadic function

See also #46

Edit style section for grammar and clarity

I added a few missing punctuations and cleaned up the wording in a few places to
make it a little clearer.
I fixed the name of the constructor in a couple of the code examples.

Update entry on Cevelop

@PeterSommerlad asked me to update the entry on Cevelop.

Added link to C++ Core Guideline

Moving link to the key part of the sentence

Address comments from #37

Update 04-Considering_Safety.md

Update 04-Considering_Safety.md

Precompiled Header

Passing and returning simple types

best idea is to use brace initialization

 * CNCC
 * ClangFormat
 * SourceMeter 
 * maiken

Add other tools section (#33)

Filled the section about precompiled headers with some general
information and some links to a manual for the common compiler

Add a other tools section and move Metrix++ entry there.
Also add ABI compliance checker to other tools section.

Minor improvements

Fixed some typos, added some links and some further minor improvements

Several minor improvements

Added some links, fixed some typos etc.