String Additions

String capitalization. Index-based insertion, replacement, and removal. Similar implementation of C# String.Format(..) to allow for terse index-based string interpolation without needing to use a literal with '$var' at the time of interpolation.
This only works for ASCII 0x20 space characters. Consider supporting a variety of whitespace characters with one of:
`new RegExp(r'(^|\s)(\w)'` or `new RegExp(r'(^|\W)(\w)'`