Add vs2019 support, remove support for vs2013 and older

The title editor window layout has been adjusted to look better on high resolution displays with larger than 100% UI scaling.

Fixing vs2012, vs2013 and vs2015 compatibility

This release comes with two different .vsix files. They contain the exact same extension DLL but with different versions of the manifest required by Visual Studio to manage/identify the extension.

• VSWindowTitleChanger.vsix comes with the new version of the manifest that allows installation with Visual Studio versions from vs2012 to vs2017. This vsix doesn't support vs2010 and older.
• VSWindowTitleChanger_old.vsix contains the old version of the manifest that allows installation with Visual Studio versions from vs2010 to vs2017 but vs2017 pops up a compatibility warning yes/no dialog.

The Visual Studio gallery will host the new .vsix file which means that vs2010 users have to download the old .vsix file from here and install manually by double clicking it.

Adding support for VS2017

• Added support for VS2017 and removed support for VS2010 because of converting to the new vsix format. As a result this release supports VS2012, VS2013, VS2015 and VS2017. Closes #10.
• Fixed a multithreading/race-condition bug that crashed VS for a lot of people.