[monodoc] Parse correctly '{' and '}' as '<' and '>' (generic params) in ECMA url.

These characters are used in place of normal bracket in some part of the xsl generation code, mostly to prevent ASP.NET default code injection policy to kick in.
[monodoc] Add reachability unit test for ASP.NET style URLs
[monodoc] Add utility property Generic*IsNumeric to distinguish between types using full generic notation (e.g. Foo<T1, T2>) or just backtick notation (e.g. Foo`2)
[IDesigner] Add cref reachability checker unit test though disabled for now.

Mono documentation has a lot of syntax error in its crefs so it's not good material for a reliable unit test until we can do better on that front.
[monodoc] Add a simple stack-based generic argument count method.
[monodoc] Remove previous horrible generic backtick notation hack and properly handle them in node search.