Add short feature description

Author: MauriceKayser

README.md

@@ -5,5 +5,12 @@ convenience macro `FromPrimitive`) to interoperate with low level, typically ope
 related types which store data with sub-byte precision, like boolean flags or sub-byte fields,
 in a type-safe, typical rust way.
 
+It supports:
+- `bool`s and C-like enums as bit flags + enumerability over flags, if C-like enums are used
+- Primitive types and C-like enums as multi-bit fields
+- Explicit and implicit positioning and sizing of fields and flags
+- Optional `core::fmt::Debug` and `core::fmt::Display` implementations
+- Compile-time overlap and boundary checking.
+
 For more specific documentation look at the documentation of the macros, or at the files in
-`examples/*`.
+`examples/*`.