Support richer patterns

This is a proposal for supporting more elaborate patterns, such as:

**Repeated bytes / sub-patterns** - Specified with curly braces:
- `ff{7,10}`

**Ranges / sets** - Specified inside square brackets:
- `[55-aa]`
- `[11,22,33]`

**String literals** - Delineated via double quotes in the pattern:
- `deadbeef1234"astring"`
