Makefile: Fix DESTDIR handling
Improved simplifications of redundant loops:
- Execute simplifyWhile0 after simplifyKnownVariables (#394)
- Support declaration of variable in loop header in removeRedundantFor
#6189 assign with operator= a '\0' to a std::string is not an error
Add VS2013 projects for my personal use (using /LTCG, /MP, /RELEASE, /MT).

[ci skip]
Add a script to run coverity with VS2013.

[ci skip]
Move astyle options to astyle.ini.

This way we can use it in runastyle and runastyle.bat.

Settings changes:
* specify the files to exclude instead of specifying the files to style
* remove `--lineend` option
* keep the file's modified timestamp
* only show the styled files on the command output

Also change the astyle version check to only check for older not the exact version.

[ci skip]
Update runastyle.bat from MPC-HC.

It includes a check if astyle is present and for astyle's version.
Also, it allows drag and dropping files onto it to style them.

[ci skip]
PEP8 fixes.