Separate WPF and common code

[ForNeVeR]

TODO

• Move the new project to src.
• Fix the test failures.
• Figure out what to do with the remaining files. See Extract WPF-dependent code into a separate project #63 for more details:
  • classes from the root namespace:
    • CharInfo,
    • SystemFont,
    • TexRenderer (probably split into two classes because it is a bit WPF-dependent),
    • give a good way to obtain some sort of default TexEnvironment;
  • take a look at the Brush-related code in the feature/17-avalonia branch;
  • the remaining classes from the root namespace:
    • TexEnvironment;
  • Boxes;
  • Box-dependent classes from the root namespace:
    • DelimiterFactory,
    • Glue,
    • GlueSettingsParser;
  • Atoms except:
    • AccentedAtom,
    • BigOperatorAtom,
    • ScriptsAtom;
  • Atom-dependent classes from the root namespace:
    • DelimiterInfo,
    • TexSymbolParser,
    • TexFormula together with the remaining Atoms:
      • AccentedAtom,
      • BigOperatorAtom,
      • ScriptsAtom,
    • TexFormulaParser,
    • TexFormulaHelper,
  • Colors;
  • Parsers:
    • root files,
    • Matrices,
    • PredefinedFormulae;
  • TexPredefinedFormulaParser (note that ColorConstantValueParser requires some portable color definition);
  • Rendering/IElementRenderer.cs.
• Rename the new project to WpfMath.Common.
• Check all the files remaining in the WpfMath project, re-plan if required.
• Think about generics.
• Re-think the API around TexFormula and TexRenderer: maybe put back the original extension methods. TexRenderer can hold the most parameters, including the scale, and renderers could be produced and applied based on it.
• Scales: make the initial size to work in the bitmap pixels/DIP, not scaled.
• TODO monitoring: perform the tasks that are possible to do in scope of this PR.
• Think about tests.
• Name monitoring: new and newly exposed classes should have TeX instead of Tex.
• Review the documentation: example renderer now is changed a bit.
• Make sure the Shared library is put into the NuGet package.
• Example app: add sliders for X an Y formula coordinates.
• Manual test all the supported frameworks.
• Synchronize with the master branch.
• We should introduce some formal way of comparing APIs for different versions and probably add a compatibility layer.
• Document the breaking changes.

Before merge

• TODO monitoring (create an issue for every TODO touched in this PR).

After merge

• Open an issue about generics (<TBrush> everywhere?). Related types:
  • IBrush
  • IFontTypeface
• Create a new issue about 1.0 release (considering all the future planned API changes).